Science terms made_easy

Science Terms
Made Easy
A Lexicon of Scientific Words and
Their Root Language Origins
Joseph S. Elias
GREENWOOD PRESS
Westport, Connecticut • London

Library of Congress Cataloging-in-Publication Data
Elias, Joseph S., 1948–
Science terms made easy : a lexicon of scientific words and their root language origins / Joseph S. Elias.
p. cm.
Includes bibliographical references and index.
ISBN 0–313–33896–5 (alk. paper)
1. Science—Terminology. 2. Latin language—Technical Latin. 3. English language—Etymology. I. Title.
Q179.E45 2007
501'.4—dc22 2006026197
British Library Cataloguing in Publication Data is available.
Copyright © 2007 by Joseph S. Elias
All rights reserved. No portion of this book may be
reproduced, by any process or technique, without the
express written consent of the publisher.
Library of Congress Catalog Card Number: 2006026197
ISBN: 0–313–33896–5
First published in 2007
Greenwood Press, 88 Post Road West, Westport, CT 06881
An imprint of Greenwood Publishing Group, Inc.
www.greenwood.com
Printed in the United States of America
The paper used in this book complies with the
Permanent Paper Standard issued by the National
Information Standards Organization (Z39.48–1984).
10 9 8 7 6 5 4 3 2 1

For all you mean to me,
this book is dedicated to my mother and father;
to my brothers, Edward and Victor;
and to my daughters, Elizabeth, Kate, and Samantha.

Contents
Preface ix
Acknowledgments xi
How to Use This Book xiii
Alphabetical Entries 1
Common Prefixes 205
Common Roots 209
Common Suffixes 217
Resources 219

Preface
The idea for writing this book came about as a result
of discussions with my pre-service science teacher
on effective ways to teach science vocabulary. Years
ago, I came to realize that high school and middle
school students viewed the complexities of scientific
vocabulary as a necessary burden that sometimes
interfered with their pursuit of understanding impor-
tant concepts. Students at these grade levels would
complain about words that were unfamiliar or unrec-
ognizable. Quite often science teachers new to the
profession would address the vocabulary by develop-
ing word lists and definitions or by coming up with
simple word association games promoting the ability
to recognize words and recall their meanings.
During my years as a teacher of human anatomy
and physiology, I developed a student assignment
called the “List of 50 Muscles.” Students were pro-
vided with a list of the muscles, and their task was to
examine the names and describe all they could about a
given muscle simply by analyzing the name. Muscles
such as the pterygoideus internus, the external carpi
radialis longus, or my favorite, the sternocleidomastoi-
deus, challenged students to go beyond the words
themselves and, in a sense, dissect the word as they
would if they were dissecting a preserved specimen.
Students discovered that the parts of these scientific
terms could be interchanged and still retain their
meanings.
As you might imagine, for me as a young teacher,
this was a breakthrough of sorts. I became as strong an
advocate for inquiry-type teaching approaches to sci-
entific terminology as I was for the teaching of inquiry
methods in science itself. I found a way to once again
challenge students to think, analyze, and reason their
way to a deeper understanding rather than resort to rote
memorization.
This, of course, led me to more deeply examine
the terminology that I used on a regular basis in all
my science classes. I became more curious about the
origins and the history of the words. If a student
wanted an explanation of a given word, I wanted to
be prepared to either point the student in a direction
where he could find an answer or, sometimes, to sim-
ply tell the tale myself.
What I discovered was that words have histories.
They move through cultures and times and mutate
along the way. So when you examine the list, you
will find descriptions of many roots that will call
upon you to make the connections between the origi-
nal meanings of the roots and their modern counter-
parts. Sometimes making those connections is a
stretch, and you’ll have to use your imagination. But
through all of this, I found the literal meanings to be
simple, if not humble, compared with the rather
sophisticated uses of the root words today.
I hope you will value the sidebars. You will proba-
bly notice that the ancient Greeks had much to do
with science, mathematics, and philosophy. These
great thinkers provided the world with its first really
grand period of scientific enlightenment. The philoso-
phers of the time pondered the order of the universe.
They speculated and hypothesized on all aspects of
order and chaos. They spoke of the things that were
earthly and of things that were divine, and they used
these models as the bases for their perception of the
physical world. Many of the terms used in science,

x Preface
especially the physical sciences, have their origins
in the Greek language.
The study of living things—anatomy, taxonomy,
and medicine—did not really move forward until
the next period of scientific enlightenment, in the
seventeenth and eighteenth centuries. By that time,
the great days of the Greek civilization were long
past and the age of exploration and investigation
moved more toward Western Europe. Thus, you will
notice that many of the root words associated with
living things are of Latin rather than Greek origin.
As a final note, this compilation of words is by
no means meant to be a complete text of scientific
terminology, but it does represent a very healthy
collection of the more common words used in sci-
ence courses in middle and high school science
classes. I imagine that students in lower-division
college courses will also find this book to be a
valuable reference. It is my sincere hope that
readers will have as much fun with this compila-
tion of science terminology as I had putting it all
together.

Acknowledgments
First and foremost, I wish to acknowledge the many
science education students at Kutztown University
for their significant contributions to my list of
words. Without them, the task of gathering infor-
mation and developing the final product would have
been far more daunting of an undertaking.
I would also like to acknowledge the members of
the Department of Secondary Education at Kutztown
University. Their support, expertise, guidance, and
patience allowed me to focus on the task at hand.
I would also like to thank the regional science
teachers who, on occasion, would e-mail or pass
along words that caught their interest.

How to Use
This Book
I have never underestimated the creativity of teach-
ers. When they were given the right tools and the
proper amount of time, the teachers that I have known
developed some fascinating perspectives on how to
teach science. Virtually all experienced and talented
science teachers pride themselves on being able to
challenge students to think, reason, predict, hypothe-
size, and interpret data collected from observation
and experimentation. This book provides another
valuable component to assist them in their efforts.
Teaching scientific terminology for understand-
ing has always been a challenge for teachers. The
words included in this text will provide the teacher
with a source for integrating complex terminology
into their lessons. I recommend that instructors
design activities that call for students to critically
examine the words they are learning in ways that
encourage them to look deeper into their meanings
and historic origins. The sidebars provide historical
perspectives and a quick study of interesting people
and events that led to the study of science and tech-
nology in the modern era. The reader will gain an
appreciation of how scientists, mathematicians, and
philosophers of past eras were able to develop theo-
ries of the order of the universe based on reason
rather than experimentation. Many of these theories
went unchallenged for over a thousand years.
I would encourage students to become very
familiar with the common prefixes and suffixes.
Suffixes such as -or and -ion appear repeatedly in
words pertaining to actions or processes. Prefixes
such as a- or an- and con- or com- are very common
in scientific language. If students are made aware of
how these word fragments are used, they should be
able to recognize their relevance in terms that are
new to them. Teachers may also want to point out
that the o’s have been deliberately removed from
many of the word fragments, the reason being that
they are generally referred to as “combining vow-
els.” The o is used to connect many commonly used
prefixes and suffixes to the root words; such, for
instance, is the case with stern-o-mastoid.
This inquiry approach to language not only
strengthens the analytical skills of students, it also
fosters a sense of independence in the learner.
Students quickly learn that they have the power to
examine complex words and construct new mean-
ings independently of a teacher or professor.

Abdomen
Latin
abdomen belly, venter
That portion of the body that lies between the
lower thorax (chest) and the pelvis.
Abdominalgia
Latin/Greek
abdomen- belly, venter
-algia pain, sense of pain; painful; hurting
Pain in the abdomen; a belly ache.
Abductor
Latin
ab- off, away from
-ducere- to draw or lead
-or a condition or property of things or persons,
person that does something
The name given to the function of a skeletal mus-
cle used to pull a body part (arm or leg) away
from the midline of the body.
Aberration
Latin
aberrare- deviation from the proper or expected
course
-ion state, process, or quality of
The bluring or distortion of an image, typically
caused by a defect in the lens.
Abiocoen
Greek
a- without
-bios- life, living organisms or tissue
-coen common, shared
The sum total of the nonliving components of an
environment.
Abiotic
Greek
a- without
-ic (ikos) relating to or having some characteristic of
The set of nonliving environmental factors or
conditions that are common within a given eco-
logical system.
Abrasion
Latin
abradere- to scrape off
The process of wearing down or scraping off by
means of rubbing one object against another object.
Abscess
Greek
ab- off, away from
-c dere to go
A localized collection of pus in part of the body,
formed by tissue disintegration and surrounded
by an inflamed area.
Abscission
Latin
ab- off, away from
-caedere- to cut
The shedding of leaves, flowers, or fruits follow-
ing the formation of the abscission zone.
Absorbance
Latin
ab- off, away from
-sorbere- to suck
-ance brilliance, appearance
e

2 Abyssal
The relative ability of the surface of a substance
to retain radiant energy.
Abyssal
Greek
a- without
-bussos- bottom
-al of the kind of, pertaining to, having the form
or character of
Of or relating to the region of the ocean bottom
between the bathyal and hadal zones, from depths
of approximately 3,000 to 6,000 meters.
Acanthaceous
Greek/Latin
akanthos- thorn plant
-aceous having the quality of
Resembling or having the quality of the family of
plants that bear prickles or spines.
Acanthologist
Greek
akanthos- thorn plant
-logist one who speaks in a certain manner; one
who deals with a certain topic
A person who studies spines or spiny creatures.
Acapnia
Greek
a- no, absence of, without, lack of, not
-kapnos smoke, carbon dioxide (CO2)
A condition marked by the presence of less than
the normal amount of CO2 in blood and tissue.
Acardia
Greek
-kard- heart, pertaining to the heart
-ia names of diseases, place names, Latinizing
plurals
A congenital condition, usually occurring with
twins, where one of the two siblings is born with-
out a heart, or a lone heart is shared by the two.
Acaulescent
Latin
-caulis- stem
-escent being in a specific state, beginning to be
A seemingly stemless plant, though the stem may
be small and sometimes belowground.
Accipitrine
Latin
accipiter- hawk
-ine of or relating to
Raptorial, hawklike, belonging to the genus
Accipiter.
Acclimation
Greek
-klime- slope
Physiological responses to environmental change.
Accommodation
Latin
ad- to, a direction toward, addition to, near
-commodus- to adjust, suitable
Thestateorprocessofadjustingoneitemtoanother.
Accuracy
Latin
accuratus- done with care
-cy state, condition, quality
Precision, exactness.
Acetabulum
Latin
aceta- hip
-bul- place for
-um (singular) structure
-a (plural) structure
Cup-shaped cavity at the base of the hipbone.
Acetylcholine
Latin/Greek
acetum- vinegar
-khole- bile
-ine a chemical substance
A neurotransmitter that mediates the synaptic
activity of autonomic synapses and neuromuscular
junctions.
Acheiria
Greek
-chir- hand; pertaining to the hand or hands
-ia names of diseases, place names, or Latinizing
plurals
Congenital absence of the hands.
Acidaminuria
Latin
acere- to be sour
-amino- relating to an amine or other compound
containing an NH2 group
-urina urine
A disorder involving the metabolism of protein
where excessive amounts of amino acids are
found in the urine.
Acidemia
Latin
acere- to be sour
-haima blood

Actophilous 3
A medical condition in which blood pH is below
normal.
Acidic
Latin
acere- to be sour
Having the reactions or characteristics of an acid.
Acidiferous
Latin
acere- to be sour
-ferrous bear, carry; produce
Producing or yielding an acid.
Acidize
Latin/Greek
acere- to be sour
-ize to make, to treat, to do something with
To treat with acid.
Acidosis
New Latin
acere- to be sour
-sis action, process, state, condition
The condition in which there is an excessive
amount of acid in the blood.
Acoelomate
Latin/Greek
-coelom- (koilomat) cavity
-ate an organism having these characteristics
An organism lacking a body cavity between the
gut and the outer musculature of the body wall.
Acology
Greek
aco- remedy, cure
-logy (logos) used in the names of sciences or
bodies of knowledge
The science of remedies; therapeutics.
Acroanesthesia
Greek
acro- outermost; extreme; extremity of the body
-an- without, not
-aisthesis- feeling
-ia names of diseases, place names, or
Latinizing plurals
Loss of sensation in the extremities; such as the
hands, fingers, toes, and feet.
Acrodendrophile
Greek
acro- high, highest, highest point; top, tip end,
outermost; extreme
-dendron- tree, treelike structure
-phile one who loves or has a strong affinity or
preference for
In biology, describing a species that lives or
thrives in treetop habitats.
Acromegaly
Greek
outermost; extreme
-megas large, big, great
A chronic disease in which the bones of the
extremities, face, and jaw become enlarged.
Acrosome
Greek
outermost; extreme
-soma (somatiko) body
A caplike structure at the anterior end of a sper-
matozoon that produces enzymes aiding in egg
penetration.
Actin
Latin
ctus- motion
- nus relating to
A protein found in muscle that, together with myo-
sin, functions in muscle contraction.
Actinoid
Greek
aktin- ray (as of light), radiance, radiating
-oid (oeid s) resembling; having the appearance of
Having a radial form, as a starfish.
Actinotherapy
Greek
aktin- ray (as of light), radiance, radiating
-therapeuein heal, cure; treatment
Treatment of disease by means of light rays.
Activation
Latin
ctus- to set in motion
Stimulation of activity in an organism or chemical.
Activity
Latin
activus- to drive, do
-ity state of, quality of
The state of being active; energetic action or
movement; liveliness.
Actophilous
Greek
acto- seashore, beach
-phile- one who loves or has a strong affinity or
preference for
-ous full of, having the quality of, relating to
In biology, organisms thriving on rocky seashores
or growing on coasts.
a
i
e
a

4 Acuminate
Acuminate
Latin
acus- (acuere) to sharpen; needle, point
-ate characterized by having
Describing the tip of some leaves tapering gradu-
ally at the end to a point.
Acute
Latin
acus sharp; needle
Severe and sharp, as in pain.
Adactylia
Greek
-daktulos toe, finger, digit
The absence of digits on the hand or foot.
Adaptation
Latin
-aptare- fit, fitted, suited
Modification of an organism or its parts that
makes it more fit for existence under the condi-
tions of its environment.
Adduct
Latin
-ducere to lead, bring, take, or draw
To draw inward toward the median axis of the
body or toward an adjacent part or limb.
Adductor
Latin
-ducere- to lead, bring, take, or draw
-or a condition or property of things or persons;
person who does something
Any muscle used to draw a body part toward the
midline of the body.
Adelopod
Greek
-delo- visible, clear, clearly seen, obvious
-pod foot
An animal whose feet are not apparent.
Natural Selection
Over a century ago two men put forth a coherent
theory about the origin of new species. The expla-
nation was really quite simple and was based
mostly on observations of the natural world. Yet
today people in the Western world continue to con-
test the validity of the theory of evolution based on
natural selection.
Charles Darwin and Alfred Russell Wallace
contended that the world is full of different species,
and that any species, if allowed to do so, will grow
at a prolific rate, producing far more progeny than
can be handled by its environment. The results are
readily observable: the excess population of a given
species tends to die off, leaving behind an accept-
able number of organisms given the available
resources. Darwin believed that the organisms that
manage to survive do so because they are best
adapted to the particular set of environmental con-
ditions in which they exist. Since survivors tend to
live to reproduce, those managing to do so would
pass on to the next generation the same or similar
genetical traits that allowed them to be among the
“selected.” And because organisms tend do what
comes natural—eat, drink, seek shelter, and
breed—the progeny or filial generation would
invariably be confronted with environmental
stresses influencing their ability to carry out the
first three of these natural functions, leading to the
imposition of a selective process on their numbers
and leaving the survivors to breed among
themselves—that is, assuming they are sexual in
their habits
Now multiply this process by the time allotted
for each generation—which is considerably longer
for humans than for rats, for instance. The number
of offspring produced by fertile females varies, as
does their reproductive viability (how often they
reproduce). When we compare the number and fre-
quency of births for rats with those of even more
prolific species, such as fleas or bacteria, we natu-
rally find that the more prolific a species is, the
greater the likelihood of diversity in genotype and
phenotype.
It is all about adaptability. Through selection,
over time species tend to become more in tune with
their environment. Because of successful adapta-
tion and continual breeding, any given species has
the capacity to produce genetic mutations. These
continual, chance changes in genetic code over
extreme periods of time have the potential of mod-
ifying the individuals of a given species to the point
to where they significantly differ from their ances-
tors. These genetically produced modifications are
“tested” against environmental conditions and are
either selected for or selected against based on
whether the organism lives long enough to breed.

Advection 5
Adenalgia
Greek
aden- lymph gland(s)
-algia pain, sense of pain; painful, hurting
A painful swelling in a gland.
Adendric
Greek
-dendr- tree, resembling a tree
Without dendrites.
Adenine
Greek
A white crystalline base found in various animal
and vegetable tissues as one of the purine base
constituents.
Adenitis
Greek
-itis inflammation, burning
Inflammation of a lymph node or of a gland.
Adenocarcinoma
Greek
-karkinos- crab, cancer
-oma tumor, neoplasm
A malignant tumor originating in glandular
epithelium.
Adenofibrosis
Greek/Latin
-fibre- an elongated threadlike structure
Fibroid change in a gland.
Adenoid
Greek
Glandlike lymphoid tissue, similar to the tonsils,
located high in the back of the pharynx.
Adenovirus
Greek
-v rus poison
Any of a group of DNA-containing viruses that
cause conjunctivitis and upper respiratory tract
infections in humans.
Adhesive
Latin
-haerere- stick to, cling to
-ive performing an action
Tending to cling; sticky.
Adiabatic
Greek
-diabatos- passable
Of, relating to, or being a reversible thermody-
namic process that occurs without gain or loss of
heat and without a change in entropy.
Adipocyte
Latin
adip- of or pertaining to fat
-cyte (kutos) sac or bladder that contains fluid
A mature fat cell found in animals.
Adiponecrosis
Greek
-necro- death
Death of fatty tissue occurring in hemorrhagic
pancreatitis.
Adipose
Latin
-ose sugar, carbohydrate
Of a fatty nature; the fat present in the cells of adi-
pose tissue.
Adjuvant
Latin
-jungere- to join or unite
-an one that is of, relating to, or belonging to
A substance added to a vaccine to increase its
effectiveness.
Adrenal
Latin
-ren- the kidneys
or character of
Glands located on top of the kidneys.
Advection
Latin
-vehere- to carry
The transfer of a property of the atmosphere, such
as heat, cold, or humidity, by the horizontal
movement of an air mass.
e
i

6 Adventitious
Adventitious
Latin
-vent- come
Describing buds of a plant developing in intern-
odes or on roots.
Adynamandrous
Greek
a- without
-dunamikos- powerful
-androus man, men, male, masculine
Having nonfunctioning male reproductive organs.
Aerenchyma
Latin
aer- air, atmosphere, mist, wind
-enchyma tissue
Large air-filled cells that allow rapid diffusion of
oxygen within wetland plants.
Aerobacter
Greek
-bacter rod-shaped microorganism
Any genus of bacteria normally found in the
intestine.
Aerobic
Greek
-bio- life, living organisms or tissue
Pertaining to organisms or processes that require
the presence of oxygen.
Aerobiont
Greek
-bio- life, living organisms or tissue
-ont (einai) to be
Either an organism living in air as distinct from
water or soil or an organism requiring oxygen.
Aerolite
Greek
-lite- (lith) stone or rock
A meteorite that is composed of a siliceous stony
material.
Aerophilous
Greek
preference for
Refers to plants that are pollinated by wind or fer-
tilized by airborne pollen.
Aerotaxis
Greek
-taxis order or arrangement
Movement of an organism in response to the pres-
ence of molecular oxygen.
Affect
Latin
-facere to do, carry, bear, bring
To act upon or have an influence upon some
behavior.
Affector
Latin
-facere- to do, carry, bear, bring
In biology, the term given to a nerve cell.
Afferent
Latin
-facere- to do, carry, bear, bring
-ent causing an action, being in a specific state,
within
Leading toward a region of interest; carrying
toward the center of an organ or section, such as
nerves that conduct impulses from the body to the
brain or spinal cord.
Agantha
Greek
a- without
-gnatha jaw
A superclass of fish that lack a jaw and a pelvic fin.
Agglutination
a- without
-glutinare- to glue
The process by which red blood cells clump
together.
Agonist
Greek
agon- conflict, contest
-ist one who is engaged in
A muscle that is contracting and has an opposing
muscle (antagonist) applying force on a bone in
the opposite direction.

Albinism 7
Agriculture
Latin
agros- of or belonging to fields or soil
-colere to till
The science, art, and business of cultivating soil,
producing crops, and raising livestock; farming.
Agroforestry
Greek/Latin
agros- of or belonging to fields or soil
-foris- outside
-y place for an activity, condition, state
Land management for simultaneous production
of food crops and trees.
Aigialophilous
Greek
aigial- beach, seashore, cliff
preference for
A community of organisms that thrive in beach
habitats or among pebbles on the beach.
Albedo
Latin
albus- the color white
The ability of the surface of a planet or a moon to
reflect light.
Albinism
Latin
albus- the color white
-ism state or condition, quality
The state or condition of being an albino; a group of
inherited disorders characterized by deficiency or
absence of pigment in the skin, hair, and eyes due to
an abnormality in the production of melanin.
George Washington Carver
“Our creator is the same and never changes despite
the names given Him by people here and in all parts
of the world. Even if we gave Him no name at all,
He would still be there, within us, waiting to give us
good on this earth.”
—G.W. Carver
How eloquent this humble man and inventor
was during his life. George Washington Carver was
born in 1864, near the end of the American Civil
War, in Diamond Grove, Missouri. In these trou-
bled times, Carver was kidnapped along with his
mother by Confederate night raiders and wound up
in Arkansas. Moses Carver, the owner of the farm
that was George’s birthplace, later found George
and reclaimed him. He and his wife, Susan, raised
George as their own. His natural mother was never
found, and the identity of his father was not known.
He left home at the tender age of 12 to begin his
schooling. George suffered all the setbacks associ-
ated with racial segregation. He was the first black
student ever to be admitted into Simpson College of
Indianola, Iowa. There he studied piano and art, but
George wanted to study science, so he transferred
to Iowa Agricultural College in 1891, when he was
27 years old. George was a diligent student; he
earned both a bachelor’s and a master’s degree in
bacterial botany and agriculture in 1897 and
became the first black member of the Iowa college.
Later that year, George Washington Carver
moved to Tuskegee, Alabama, to become the Direc-
tor of Agriculture at the Tuskegee Normal and
Industrial Institute for Negroes. It was here that
Carver began a career that has impacted the lives of
millions. He helped revolutionize agricultural prac-
tices in the war-torn South. As a result of the con-
tinuous planting of either cotton or tobacco,
southern plantations had become virtually useless.
Carver taught farmers about crop rotation for the
purpose of enriching the fields with nutrients. He
taught them how to grow peanuts, soybeans, sweet
potatoes, and other soil-enriching crops. This
brought the South back to life again.
George Washington Carver was never interested
in wealth or profit from his work. He lived by his
words: “How far you go in life depends on your
being tender with the young, compassionate with
the aged, sympathetic with the striving, and toler-
ant of the weak and strong. Because someday in
your life you will have been all of these.” He held
three patents, but he did not patent the numerous
discoveries he made while at Tuskegee. He created
over 300 products from peanuts and more than 100
products from sweet potatoes.
Carver was a compassionate teacher. He taught
his students to love nature and to use the forces of
nature for the benefit of all. He believed that educa-
tion should be “made common” and that all mem-
bers of the community would profit by an educated
society.
George Washington Carver died in 1943. He
was honored by President Franklin Roosevelt with
a national monument, the first for an African
American, near Diamond Grove, the place of his
childhood.
e

8 Albumin
Albumin
Latin
albumo- the color white
-in protein or derived from a protein
Blood plasma protein produced in the liver.
Alcohol
Med. Latin from Arabic
al- the
-kuhl- essences obtained by distillation
-ol alcohol
Any of a series of hydroxyl compounds having
the general formula CnH2n+1OH.
Aldehyde
Latin
al. dehyd- short for alcohol dehydrogenate
Any of a class of highly reactive organic chemical
compounds obtained by oxidation of primary
alcohols.
Aldosterone
Greek/Latin
al. dehyd- dehydrogenized alcohol
-stereos- solid
-one chemical compound containing oxygen in a
carbonyl group
A steroid hormone secreted by the adrenal cortex
that regulates the salt and water balance in the body.
Algae (alga)
Latin
alga seaweed
A very large, diverse group of plantlike organ-
isms that are mostly aquatic or marine. They
range from the unicellular forms to the extremely
large kelp forms.
Algaecide
Latin
alga seaweed
-cide (caedere) to cut, kill, hack at, or strike
Type of pesticide that controls algae in bodies of
water.
Algesimeter
Greek
algeis- pain
-meter (metron) instrument or means of measur-
ing; to measure
Aninstrumentusedtomeasurethesensitivitytopain,
suchasthatproducedbyprickingwithasharppoint.
Algesiogenic
Greek
algeis- pain
-gen- to give birth, kind, produce
Producing pain.
Alimentary
Latin
alimentum- nourishment, supplying food
-ary of, relating to, or connected with
Pertaining to food or nourishment and to the
digestive system/alimentary canal.
Alinasal
Latin/Greek
ala- wing
-nasus- nose
or character of
Pertaining to the flaring of the nostrils.
Aliphatic
Greek
aleiphein- to anoint with oil
Of or relating to a group of organic chemical
compounds with carbon atoms linked in open
chains.
Alkalimeter
Latin (from Arabic)/Greek
alkali- (Latin) basic (pH more than 7)
alqili- (Arabic) ashes (originally from Arabic
word al-qali, which means “ashes,” and recalls
the elements Na [sodium] and K [potassium] left
in the ashes of burning wood or plants)
ing; to measure
An apparatus for measuring concentrations of
alkalinity in solutions.
Alkaline
Relating to or containing the carbonate or hy-
droxide of an alkali metal (the aqueous solution
of which is bitter, slippery, caustic, and basic).
Alkalosis
The condition in which there is an excessive
amount of alkali in the blood.

Altruism 9
Alkane
English/Arabic/French
alkyl- (English) alcohol
al-kuhl- (Arabic)al- the + kuhl powder of antimony
-(meth)ane an odorless, colorless gas (CH4)
Any member of the alkane series.
Alkene
al-kuhl-(Arabic)al-the+kuhlpowderofantimony
-ene an unsaturated organic compound
Any of a series of unsaturated, open-chain hydrocar-
bons with one or more carbon-carbon double bonds.
Alkyne
al-kuhl- (Arabic) al- the + kuhl powder of anti-
mony
-ine a chemical compound
Any of a series of open-chain hydrocarbons with
a carbon-carbon triple bond.
Allele
Greek
alleion mutually
Oneoftwoormorealternativeformsofagene,occu-
pying the same position on paired chromosomes
and controlling the same inherited characteristic.
Allergen
Greek
allos- other, different
-gen to give birth, kind, produce
A substance, such as pollen, that causes an allergy.
Alliaceous
Latin
allium- onion, garlic bulb
Of or pertaining to the botanical genus Allium.
Allometry
Greek
-metria (metron) the process of measuring
The patterns of relationships among structure,
function, and size.
Allosaur
Greek
-sauros lizard
Any one of a group of dinosaurs existing in the
late Jurassic and early Cretaceous periods. They
had features similar to those of the tyrannosaur,
but were small.
Allotropy
Greek
-trope- bend, curve, turn, a turning; response to a
stimulus
The existence of two or more crystalline or
molecular structural forms of an element (rotat-
ing light in different directions).
Alloy
Latin
alligare- to bind
The state of mixing two or more metallic sub-
stances where the combination calls for each metal
to occupy spaces within the molecules of the other.
Alluvion
Latin (alluere)
-luere- to wash
The process by which the wash or flow of water
inundates a land mass; to wash against.
Altimeter
Latin
altus- high, highest, tall, lofty
ing, to measure
A barometer-like device that is used in airplanes
to determine altitude.
Altitude
Latin
altus- high, highest, tall, lofty
-ude state, quality, condition of
In astronomy, the angle between an object in the
sky and the horizon.
Altricial
Latin
alere- to nourish
or character of
Referring to various bird species in which
hatchlings are typically weak, naked, and depen-
dent on their parents.
Altruism
Latin
alter- other
Instinctive cooperative behavior that is detrimen-
tal to the individual but contributes to the survival
of the species.

10 Alveolus
Alveolus
Latin
alveus hollow, belly
Microscopic air-containing sacs in the lungs where
gases are exchanged during external respiration.
Amalgam
Greek
-malgama soft mass
A combination of different elements sometimes
mixed with mercury to create an alloy used in
dentistry.
Amalgamate
Greek
amalgama- mixture
-ate a derivative of a specific chemical compound
or element
To combine or mix a group of elements into an
integrated whole; the substance remains a mix-
ture or alloy.
Amblyopia
New Latin
ambly- dull, dim
-optic- eye, optic
plurals
Reduced or dim vision; also called lazy eye.
Ambulacrum
Latin
ambula- walk
-crum planted with trees
One of the five radial areas on the undersurface of
the starfish, from which the tube feet are pro-
truded and withdrawn.
Amictic
Greek
-miktos- mixed or blended
Pertaining to female rotifers, which produce only
diploid eggs that cannot be fertilized, or to the
eggs produced by such females.
Ammeter
French/Greek
am- (ampere) named for Andre Marie Ampere
ing, to measure
A device used to measure electrical current in
amperes.
Ammine
Latin
ammonia- a colorless, pungent gas, NH3
-ine a chemical compound
Any of a class of inorganic coordination com-
pounds of ammonia and a magnetic salt.
Ammophilous
Greek
ammo- sand, sandy beach
preference for
In biology, vegetation that thrives in sandy beach
habitats.
Amniocentesis
Greek
amnion- embryo, bowl, lamb
-kentein- to prick, puncture
A surgical procedure in which a small sample of
amniotic fluid is drawn from the uterus through a
needle inserted in the abdomen.
Amniotic
Greek
Of or relating to the amnion, the sac or fluid that
protects the embryo (as in amniotic sac or amni-
otic fluid).
Amoeba
Greek
ameibein to change
One-celled aquatic or parasitic organism belong-
ing to the genus Amoeba, appearing as a mass of
protoplasm with no definite shape.
Amoeboid
Greek
ameibein- to change
Amoeba-like in putting forth pseudopodia.
Amorphous
Greek
-morph- shape, form, figure, or appearance
Substance with a disjointed, incomplete crystal
lattice or without shape.
Amphibian
Latin
amphi- on both or all sides, around
-an one that is of or relating to or belonging to
e

Analog 11
An animal capable of living both on land and in
water.
Amphibious
Greek
Relating to organisms that are able to live both on
land and in water.
Amphiboles
Greek
-bol (ballein) to put or throw
Any of a large group of structurally similar
hydrated double-silicate minerals.
Amphigean
Greek
-ge- earth, world
Extending all over the earth, from the equator to
both poles.
Amphioxus
Greek
-oxus sharp
Small, flattened marine organism with a noto-
chord (but no true vertebrae), which gives it a
pointed shape; the lancelet.
Amphipathic
Greek
-path- suffering, disease
Relating to protein molecules with one surface
containing hydrophilic and the other hydrophobic
amino acid residues.
Amphoteric
Greek
ampho- (amphoteros) both, each of two
Capable of reacting chemically as either an acid
or a base.
Amplitude
Latin
amplus- large, full
-ude state, quality, or condition of
The maximum displacement of wave from a rest
position; the measurement of a wave from the
normal to the height of the wave (crest) or to the
depth of the trough.
Ampulla
Latin
-phoreus bearer
Any membranous bag shaped like a leathern bot-
tle, as the dilated end of a vessel or duct; especially,
the dilations of the semicircular canals of the ear.
Amygdala
Greek
amygdale almond
An almond-shaped region of the brain, located in
the medial temporal lobe, believed to play a key
role in the emotions.
Amylopsin
Greek
amulon- starch; not ground at a mill
-tripsis- a rubbing (so named by its first being
obtained by rubbing a pancreas with glycerin)
-in protein or protein derivative
The starch-digesting amylase produced in the
pancreas.
Amyotonia
Greek
a-, ano- no, absence of, lack of, without, not
-myo- muscle
-tonia, -tone tension, pressure
Generalized absence of muscle tone, usually
associated with flabby musculature and an
increased range in passive movement at joints.
Anabolism
Greek
ana- anew, up
-bol- (ballein) to put or throw
Building of complex molecules within a cell.
Anaerobe
Greek
an- no, absence of, without, lack of, not
-aerobe organism requiring oxygen to live
Organism that can live in the absence of atmo-
spheric oxygen.
Analgesic
Greek
-algesi- pain, sense of pain; painful, hurting
Referring to compounds that reduce pain perception.
Analog
Greek
analogos proportionate
In chemistry, a compound in which one or more
elements are replaced by other elements.

12 Analysis
Analysis
Greek
ana- anew, up
-ly- (luein) to loosen, dissolve, dissolution, break
Resolving or separating a whole into its elements
or component parts.
Anaphase
Greek
ana- anew, up
-phase a stage
The third of four stages of nuclear division in mito-
sis and in each of the two divisions of meiosis.
Anastomosis
Greek
ana- anew, up
-stoma- mouth
The connection of separate parts of a branching
system to form a network, such as blood vessels.
Anatomy
Greek
ana- anew, up
-temnein to cut
The structure of an animal or plant and any of its
parts.
Anconitis
Greek
ancon- elbow
-itis inflammation, burning sensation
An inflammation of the elbow joint.
Androecium
Greek
andros- male
-oikos house
Part of a flower that produces male gametes, or
pollen grains.
Androgen
Greek
andros- male
Male hormone secreted mostly by the testes and
to a lesser amount by the adrenal cortex.
Andronosia
Greek
andros- male
-nosia disease
Diseases occurring most often in males.
Claudius Galenus of Pergamum
In the annals of medicine, the writings and teaching
of one Claudius Galenus, better known as Galen,
overshadow those of any other individual. The
medical perspectives of this ancient Greek physi-
cian occupied a position of prominence in the train-
ing of physicians throughout Europe for over a
thousand years. Galen was born in 129 AD in the
city of Pergamum, known today as Bergama, Tur-
key. Like many of the more learned people of his
time, he had a wide range of interests, including
astronomy, philosophy, astrology, and agriculture.
He chose to focus on medicine. After studying
medicine in Alexandria and Corinth, he practiced
wound treatment in gladiatorial schools.
He moved to Rome, where he began his career
as a lecturer and very quickly established himself
as an expert in the field. Soon he was appointed
physician to the Roman emperor Marcus Aurelius
and later to his son Commodus.
Galen found himself in Rome at a time when
the Roman Empire was at constant war with fac-
tions on its northern border. As the empire slowly
crumbled around him, Galen spent his years in
Rome doing what he did best, dissecting animals.
It was this work that laid the foundation for the
practice of medicine for over a thousand years. It
wasn’t a pretty sight to behold. Galen often dis-
sected live animals, and he would cut certain
nerve bundles to observe what happened as a
result. Galen was able to identify the causes of
paralysis by severing the spinal cords of pigs; he
cut the nerve controlling vocalization in the larynx
and, of course, discovered that the animal became
incapable of making sounds. He noted that blood
was carried through vessels, and he made accurate
observations about the brain that were contrary to
Aristotle’s notions of the roles of the brain and the
heart in the origination of conscious thought. He
had numerous scribes record his observations and
draw the organs and blood vessels of the dissected
animals, and this resulted in one of the major
works based on his research. This seventeen-
volume classic was titled On the Usefulness of the
Parts of the Human Body.
Galen did not, however, do significant work
with the human torso. Therefore, centuries later,
quite a few of Galen’s anatomical drawings proved
to be less than accurate, and it became necessary to
rob graves and to seek out the bodies of freshly exe-
cuted prisoners for dissection.

Angular 13
Anemia
Greek
-haima blood
A pathological deficiency in the oxygen-carrying
components of the blood.
Anemometer
Greek
anemos- wind
ing; to measure
Instrument used to measure wind speed.
Anesthesia
Greek
-aesthe- feeling, sensation, perception
plurals
Partial or total loss of the sense of pain, tempera-
ture, touch, etc., which may be produced by dis-
ease or an anesthetic.
Aneuploid
Greek
-neur- nerve
-nervus- sinew, tendon
-ploid having a number of chromosomes that has
a specified relationship to the basic number of
chromosomes
Aberration in the chromosome number, in which
one or more extra chromosomes are present.
Aneurysm
Greek
-eurus- a widening; broad, wide
Abnormal dilation of a blood vessel due to a con-
genital defect or weakness of the wall of the vessel.
Angialgia
Greek
angeion- vessel, usually a blood vessel
Pain in a blood vessel.
Angiectasis
New Latin
-ectasis expansion, dilation
Abnormal dilation of a blood vessel.
Angiitis
Greek
Inflammation of a blood or lymph vessel.
Angina
Greek
ankhon a strangling
A squeezing chest discomfort; angina pectoris
occurs when blood oxygen is cut off from por-
tions of the heart.
Angiocarditis
Greek
Inflammation of the heart and great blood vessel.
Angiocarp
Greek
-karpos fruit
A tree bearing fruit enclosed in a shell, involu-
crum, or husk.
Angiolith
Greek
-lithe stone, rock
A calcareous deposit in the wallofabloodvessel.
Angiolysis
Greek
-ly-(luein)toloosen,dissolve; dissolution,break
The obliteration of blood vessels, such as occurs
during embryonic development.
Angionecrosis
Greek
-nekros- death, corpse
-osis action, process, state, condition
Death of a blood vessel.
Angiosperm
Greek
-sperma seed
Any of a class (Angiospermae) of vascular plants
(such as orchids or roses) having the seeds in a
closed ovary.
Angular
Latin
angulus angle
Having, forming, or consisting of an angle or
angles.
e

14 Anhydride
Anhydride
Greek
-hydr- water
-ide binary compound
A chemical compound formed from another by
the removal of water.
Anhydrous
Greek
-hydr- water
A compound in which all water has been
removed, usually through heating.
Anisotropic
Greek
-isos- equal
stimulus
Not isotropic; having different properties in dif-
ferent directions; thus, crystals of the isometric
system are optically isotropic, but all other crys-
tals are anisotropic.
Annelid
Latin
annellus- little ring
-id state, condition; having, being, pertaining to,
tending to, inclined to
Any of a phylum (Annelida) of coelomate and
usually segmented invertebrates (such as earth-
worms, various marine worms, and leeches).
Anode
Greek
-hodós way or road
The negative terminal of a voltaic cell or battery.
Anomaly
Greek
-homolus- even
The angular deviation, as observed from the sun,
of a planet from its perihelion.
Anopheliphobia
Greek
-ophelos- advantage, use
-phob- fear, lacking an affinity for
or character of
An abnormal fear or hatred of mosquitoes.
Anorexia
Greek
-orexis- appetite
plurals
Loss of appetite, sometimes because of a disease;
anorexia nervosa.
Anoxia
Greek
-oxo- oxygen
plurals
Deprivation of oxygen that rapidly leads to col-
lapse or death if not reversed.
Antacid
Greek
anti- opposing, opposite, against
-acere to be sour
Any substance that reduces stomach acid.
Antagonist
Greek
-agon- conflict, contest
A muscle or muscles that move in opposition to
an agonist.
Antarctica
Greek
ante- before or prior to
-arc- bow arch or bent
A body of land found mostly south of the Artic
Circle. It covers an area of 5,500,000 square
miles. About 98% of the land mass is covered
with a thick continental ice sheet, and the remain-
ing 2% is barren rock.
Anterior
Latin
-or a condition or property of things or persons
Located near or toward the head in lower animals.
Anther
Greek
anth- flower; that which buds or sprouts
-er one that performs an action
Pollen-bearing part of a stamen.
Antheridia
Greek/Latin
-oidium fungus

Anticline 15
A sperm-producing organ occurring in seedless
plants (fungi and algae).
Anthodite
Greek
-ite minerals and fossils
A period of the Paleozoic, spanning the time
between 440 and 410 million years ago.
Anthophilous
Greek
preference for
In biology, attracted to, or feeding on, flowers;
living on or frequenting flowers.
Anthracite
Greek
anthrankitis- name of a fiery gem
Hard coal that burns with very little smoke or
flame.
Anthropic
Greek
anthropo- man; human being, mankind
Pertaining to humans or the period of their exist-
ence on earth.
Anthropobiology
Greek
bodies of knowledge
The study of the biological relationships of
humans as a species.
Anthropocentric
Greek
-kentron- center, sharp point
Regarding humans as the central element of the
universe.
Anthropogenic
Greek
Referring to pollutants and other impacts on nat-
ural environments that can be traced to human
activities.
Anthropoid
Greek
A group of primates that resemble humans; apes
and monkeys.
Anthropology
Greek
bodies of knowledge
The scientific study of the history, culture,
genetic conditions, and lifestyles of a given popu-
lation of humans.
Anthropozoonosis
Greek
-zoon- animal
-nosis disease
An animal disease maintained in nature by ani-
mals and transmissible to humans.
Antibacterial
Greek
-bacter- small rod
-ial (variation of -ia) relating to or characterized
by
Pertaining to a substance that kills bacteria.
Antibiotic
Greek
Any of a large class of substances produced by
various microorganisms having the power to
arrest the growth of other microorganisms or to
destroy them.
Antibody
Greek/Old English
-botah (body) the material frame of humans and
animals
Protein produced by the immune system in
response to the presence ofantigens in the body.
Anticline
Greek
-klinein sloping, to lean
A fold of the rock strata that slopes downward
from a center or common crest.
e

16 Anticoagulant
Anticoagulant
Latin
-co gulum- coagulator
-ant performing, promoting, or causing a specific
event
A non–habit-forming medication that prevents
the formation of clots in the blood.
Anticodon
Greek
-caudex book
A sequence of three nucleotides found in t-RNA.
Anticyclone
Greek
-kyklos- circle, wheel, cycle
-ne of or relating to
A system of winds rotating about a center of high
atmospheric pressure, clockwise in the Northern
Hemisphere and counterclockwise in the South-
ern, that usually advances at 20 to 30 miles (about
30 to 50 kilometers) per hour.
Antigen
Latin
Substance to which the body responds by produc-
ing antibodies.
Antimatter
Greek
-m ter mother
A hypothetical form of matter that is identical to
physical matter except that its atoms are com-
posed of antielectrons, antiprotons, and
antineutrons.
Antioxidant
Latin
-oxy- pungent, sharp
-ant performing, promoting, or causing a specific
event
A substance or enzyme that inhibits oxidation
or inhibits the loss of an electron.
Antiparticle
Latin
-particula a very small piece or part; a tiny por-
tion or speck
A subatomic particle, such as a positron, antiproton,
or antineutron, having the same mass, average life-
time, spin, magnitude of magnetic moment, and
magnitude of electric charge as the particle to which
it corresponds, but having the opposite sign of elec-
tric charge and opposite direction of magnetic
moment.
Antisense
Greek/Latin
-sent re to feel
Of or relating to a nucleotide sequence that is
complementary to a sequence of messenger
RNA. When antisense DNA or RNA is added to a
cell, it binds to a specific messenger RNA mole-
cule and inactivates it.
Antiseptic
Greek
-sepsis- putrefaction or decay
Preventing or counteracting putrefaction or decay.
Antiserum
Greek/Latin
-ser- the watery part of fluid
Animal or human serum containing antibodies
that are specific to a number of antigens.
Antitoxin
Greek
-toxikos- poison
-in protein or derived from protein
An antibody with the ability to neutralize a spe-
cific toxin.
Aortic
Latin
aort- lower extremity of the windpipe; by exten-
sion, extremity of the heart, the great artery
-ic relating to or having some characteristics of
Relating to the main trunk of the systemic arteries,
carrying blood from the left side of the heart to the
arteries of all limbs and organs except the lungs.
Apatite
Greek
apat - deceit
A natural, variously colored calcium fluoride
phosphate, Ca5F(PO4)3.
Aphasia
Greek
-phanai- speech
a
a
i
e

Appendectomy 17
plurals
A condition characterized by defective or absent
language abilities, typically caused by brain injury.
Aphelion
Greek
apo- away from
-helios- sun
The point on the orbit of a celestial body that is
farthest from the sun.
Aphonia
Greek
-phonos- voice
-ia names of disease, place names, or Latinizing
plurals
A condition characterized by the loss of one’s
voice, caused by a disease, injury to the vocal
cords, or various psychological factors.
Aplasia
Greek
-plassein- to form
-ia names of disease, place names, or Latinizing
plurals
Developmental failure of an organ or tissue to
form, or the malformation of an organ or tissue.
Apnea
New Latin
-pnea breathing or breath
Temporary cessation of breathing.
Apocrine
Greek
apo- away from, off, separate
-krinein to separate
Applies to a type of mammalian sweat gland that
produces a viscous secretion by breaking off a
part of the cytoplasm of secreting cells.
Apoenzyme
Greek
-en- in
-zuma leaven, yeast
The protein part of an enzyme to which the coen-
zyme attaches to form an active enzyme.
Apogee
Greek
-gaia earth
Pointofasatellite’sorbitthatisfarthestfromthesun.
Apogeotropism
Greek
-geo- earth, world
stimulus
-ism state or condition
The response by an organism of turning away
from the earth (e.g., plant stems growing upward).
Apomixis
Greek
-mixis mingling, intercourse
Reproduction without meiosis, or the formation
or fusion of gametes.
Aponeurosis
Greek
aponeurousthai to become tendinous
Sheetlike fibrous membrane that binds muscle to
muscle or muscle to bone.
Apopyle
Greek
-pyle gate
In sponges, opening of the radial canal into the
spongocoel.
Apparatus
Latin
-parare to make ready
A device or system composed of different parts
that act together to perform some special function.
Appendage
Latin
-pendere- to hang
-age ( ticum) (Latin) condition or state
A part or an organ that is attached to the axis of
the body (i.e., arm, leg); a structure arising from
the surface or extending beyond the tip of another
structure.
Appendectomy
Latin/Greek
-pendere- to hang
(ectomy)
-ekt- outside, external, beyond
-tomos
(temnein) to cut, incise, section
The surgical removal of the vermiform appendix.
a

18 Appendicitis
Appendicitis
Latin
-pendere- to hang
An inflammation of the vermiform appendix.
Appendix
Latin
-pendere to hang
A supplementary or accessory part of a bodily
organ or structure.
Aquatic
Latin
aqua- water
Consisting of, relating to, or being in water; an
organism that lives in, on, or near water.
Aquation
Latin
aqua- water
Theprocessofreplacementofotherligandsbywater.
Aqueous
Latin
aqua- water
-ous possessing, full of; characterized by
Relating to, similar to, containing, or dissolved in
water.
Aquifer
Latin
aqua- water
-ferre to carry
Layer of rock or sediment that allows groundwa-
ter to pass freely.
Arachnid
Latin
arakhn- spider
-id state or condition; having, being, pertaining
to, tending to, or inclined to
Arthropods characterized by four pairs of seg-
mented legs and a body divided into two regions.
Arboraceous
French/Latin
erbe- herb
A reference to a tree or woodlike substance.
Arboreal
Latin
arbor- tree
or character of
Of or pertaining to life in the trees or living things
in the trees.
Archaeocytes
Greek
archae- original, beginning, origin, ancient
Amoeboid cells of varied functions in sponges.
Archaeology
Greek
bodies of knowledge
The study of past human life and culture by the
recovery and examination of remaining material
evidence.
Archaeopteryx
Greek
-pterux wing
A primitive group of birds existing in the Jurassic
period, winged, with reptilian skin, teeth, and a
long tail.
Archean
Greek
The first formed rocks, characterized by cooling
periods 3.8 to 2.5 billion years ago.
Archegonium
Greek
-gonos- offspring
-ium quality or relationship
A flasklike reproductive organ found in mosses,
ferns, and some other gymnosperms where the
eggs are produced.
Archenteron
Greek
-enteron gut
The main cavity of an embryo in the gastrula stage.
Archeognatha
Greek
-gnatha jaw
Bristletail; insect with cylindrical body, no wings,
and three terminal “tails” with a medial caudal fil-
ament. Found in rocky areas, it is crepuscular or
nocturnal.

Arthroscopy 19
Archetype
Greek
-tupos type, model, stamp
An original model or pattern from which copies
are made or evolve.
Area
Latin
area open space
The extent of a planar region or of the surface of a
solid measured in square units.
Areola
Latin
area- a courtyard, open space
-ola little
A small ring of color around a center portion, as
about the nipple of the breast, or the part of the
iris surrounding the pupil of the eye.
Argillaceous
Latin
argillos- clay
Of the nature of clay; largely composed of clay.
Argon
Greek
-ergon work
A colorless, inert gaseous element composing
approximately 1% of the earth’s atmosphere.
Arillate
Latin
arillus- grape seed
A seed with an unusually brightly colored cover.
Arithmetic
Greek
arithmos- number
The computation of numbers having to do with
addition, subtraction, multiplication, and division.
Aromatic
Greek
aroma- smell (due to sweet smell of benzene and
related organic groups)
Of, relating to, or containing one or more six-carbon
rings characteristic of benzene series and related
organic groups.
Arteriole
Greek
arteria windpipe, artery
-ole little
Small, terminal branch of an artery that leads into
a capillary bed.
Arteriomalacia
Greek
arteria- windpipe, artery
-malacia softening of tissue
The softening of arteries, usually as a result of
some disorder.
Arteriosclerosis
Greek
arteria- windpipe, artery
-sklero- (skl roun) to harden
A chronic disease in which thickening, harden-
ing, and loss of elasticity of the arterial walls
result in impaired blood circulation.
Artery
Greek
A vessel that carries blood from the heart to the
cells, tissues, and organs of the body.
Arthralgia
Greek
arthr- joint
Pain resulting from inflammation in a joint.
Arthritis
Greek
arthr- joint
An inflammation of a joint.
Arthroplasty
Greek
arthr- joint
-plastos- (plassein) something molded (to mold)
-y place for an activity; condition, state
Surgical reconstruction or replacement of a mal-
formed or degenerated joint.
Arthropod
Greek
arthr- joint
-poda foot
Any of numerous invertebrate animals of the phy-
lum Arthropoda, including insects, crustaceans,
arachnids, and myriapods.
Arthroscopy
Greek
arthr- joint
-skopion for viewing with the eye
Visual examination of the inside of a joint with
the use of a specialized scope.
e

20 Articulation
Articulation
Latin
articulus- small joint
-ate- of or having to do with
The action of bending the joints; a movable or
fixed joint between two or more bones.
Artificial
Latin
artificialis- not natural, man-made
-ial relating to or characterized by
Produced by humans rather than occurring natu-
rally; refers to something created or modified
through the effects of human or sociological forces.
Artiodactyla
Greek
artios- even
Order including even-toed mammals (deer, cows,
sheep).
Asbestos
Greek
-sbennunai to quench
Magnesium silicate; a fibrous, incombustible,
and chemical resistance substance used for fire-
proofing and insulation.
Ascarid
Greek
askarizein- to jump, throb
to, tending to, or inclined to
Any of a family of nematode worms, including
the common roundworm (Ascaris lumbricoides),
which is parasitic in the human intestine.
Ascocarp
Greek
askos- bag
-karpos fruit
The mature, saclike fruiting body of an asco-
mycetes fungi.
Ascomycetes
Greek
askos- bag
-muk s fungus
A class of fungi containing an ascus and spores.
Ascus
Greek
askos- bag
A saclike spore capsule located at the tip of the
ascocarp in the phylum Ascomycota.
Asepsis
Latin
Astrology
The ancient Greeks bore witness to the orderly
nature of the daytime and nighttime skies. Based
on this recognition, they gave the name cosmos,
meaning “order,” to the celestial sphere. The
serenity of the cosmos apparently gave the
ancients a sense of security from the knowledge
that tomorrow’s nighttime sky would closely
resemble tonight’s.
The Mesopotamians are credited with the
advent of Western astrology in the second millen-
nium BC. They believed that the arrangement of
the stars and planets somehow influences human
existence here on earth. The term zodiac was
given to an imaginary band or belt spanning about
8 degrees on either side of the path of the sun.
Zodiac comes from the Greek word zoon, meaning
“animal” or “animal-like,” reflecting the fact that
the major constellations in the band are named
after animals or animal-like creatures. The path-
way defined by the zodiac also includes the orbital
paths of many planets in our solar system as well
as our moon. The Greeks are credited with the cre-
ation of the horoscope, which is a chart prepared
at the conception of a particular human being. By
plotting stellar and planetary positions in the
zodiac, ancient astrologers believed that the
course of one’s life could be foretold. So skillful
were these Greeks in the use of astrological charts
and prediction that over the course of human his-
tory few changes have been made to the methodol-
ogy of astrology as practiced by the Greeks.
Astrology, of course, is a pseudoscience. How-
ever, among the early Arab astrologers and later in
both Jewish and Christian sects, astrology devel-
oped into a vital component of the relationship
between man and his deity.
Astrology is as popular among the public today
as it was during the Middle Ages and before, espe-
cially in the United States. Scientists discount any
relationship between the positions of heavenly bod-
ies and prognosticative power. Most treat astrology
as it should be treated, as a source of amusement
and fun.
e

Astigmatism 21
-sepein- to decay, cause to rot
-sis action, process, state, or condition
The absence of contamination by unwanted
organisms.
Aseptic
Greek
-sepein- to decay, cause to rot
-ic (ikos) relating to or having some character-
istic of
Pertaining to the condition of being free from
germs or other infection-causing microorganisms.
Asexual
Latin
-sexus sex
Refers to reproduction in which a single parent
produces offspring that are genetically identical
to the parent.
Asphyxia
Greek
-sphyzein- to throb; pulse, heartbeat
plurals
A condition in which an extreme decrease in oxy-
gen in the body accompanied by an increase in
the concentration of carbon dioxide leads to loss
of consciousness or death.
Aspiration
Latin
-spir- breath of life, breath, breathing
The process of withdrawing fluid from a cavity or
sac by the use of a needle.
Assay
Latin
assa- pure, whole
-y place for an activity; condition or state
In chemistry, the determination of the quality of a
substance present in a sample.
Assimilate
Latin
-simulare- to make similar or alike
To consume, digest, absorb, and assimilate nutri-
ents into a living being.
Assimilation
Greek
-simulare- to make similar or alike
Process by which absorbed food molecules cir-
culating in the blood pass into the cells and are
used for growth, tissue repair, or other metabolic
activities.
Astatine
Greek
-statos- standing, stay, make firm, fixed, balanced
-ine in a chemical substance
A highly unstable, radioactive element.
Asteroid
Greek
aster- star
-oid (oeid s) resembling; having the appearance
of
Any of the small celestial bodies between the
orbits of Mars and Jupiter.
Asteroidea
Greek
aster- star
-oid (oeid s) resembling; having the appearance
of
Any of various marine echinoderms of the class
Asteroidea, characteristically having a thick,
often spiny body with five arms extending from a
central disk.
Asthenia
Greek
-sthenos- strength
plurals
Loss or lack of bodily strength or energy; weak-
ness, debility.
Asthenosphere
Greek
-sthenos- strength
-sphaira a globe shape, ball, sphere
A layer of hot, weak material located in the man-
tle at a depth between 100 and 350 kilometers;
the rock within the zone is easily deformed.
Astigmatism
Greek
-stigma- a point, mark, spot, puncture
A defect in an optical system (i.e., impaired eye-
sight) in which light rays fail to converge to a sin-
gle focal point.
e
e

22 Astrobiology
Astrobiology
Greek
astros- star
bodies of knowledge
The branch of biology that deals with the search
for extraterrestrial life and the effects of extrater-
restrial surroundings on living organisms.
Astrocyte
Greek
astros- star
A star-shaped cell, especially a neuroglial cell of
nervous tissue.
Astrology
Greek
astros- star
bodies of knowledge
The study of the positions of the stars and planets
based on the belief that they can predict the future.
Astronaut
Greek
astros- star
-nautes sailor
A traveler in space; a member of a U.S. space
crew trained to pilot, navigate, or conduct
research in outer space.
Galileo (1564–1642)
Galileo Galilei was born on February 15, 1564, in
the Tuscan region of Italy. His accomplishments in
the sciences are far too extensive to be covered in a
brief exposé. He spent most of his life studying
mathematics, astronomy, and physics. He was a
Catholic and had many friends who held esteemed
positions in the Catholic Church, but he found
himself on the defensive for his support of the
heliocentric configuration of the solar system as
described by Copernicus. For this position, in his
later years, he was put on trial and confined to
house arrest for the remaining days of his life.
Galileo is given credit for inventing the tele-
scope; he actually did not invent it but rather
refined and improved its design. With the advent of
the lens, he created a telescope that enabled him to
observe and study sunspots. This probably contrib-
uted to his loss of sight. He made it possible to see,
for the first time, the moons orbiting Jupiter. His
observations of Venus and its phases, which were
much like the phases of the moon, led Galileo to
side with the Copernican, heliocentric model of the
solar system rather than the widely accepted geo-
centric model put forth by Ptolemy. Galileo sold
quite a few of his telescopes and made a handsome
profit marketing them to seafarers.
Galileo is hailed as the standard-bearer for sci-
entific methodology. Influenced by his strong
background in mathematics, he advocated and pio-
neered experimental designs that included quanti-
fication of data. This was a dramatic departure
from earlier practices in science, where a more
philosophical, qualitative approach was the norm.
For this and other reasons, Galileo stood at odds
with the Church and with the more traditional,
Aristotelian thinkers. Looking back at his rather
radical departure from older approaches to sci-
ence, we acknowledge Galileo as the father of sci-
ence. He is also credited as the father of modern
physics and of modern astronomy.
We can confirm that Galileo had more than a
casual interest in technology. He developed a ther-
mometer using an enclosed tube, water, and
objects floating in the water. It operates on the
principles of temperature, compressed air and
buoyancy, and displacement. He designed and
developed the first compound microscope with
concave and convex lenses. Galileo also created a
vastly improved version of the military compass,
paving the way for improved weaponry. His mili-
tary compass provided a much safer way of elevat-
ing and supporting cannons, increasing their
firepower and accuracy.
Galileo studied pendulums and noted that the
period of the swing is independent of the wave’s
amplitude. The advent of the pendular clock later
developed by Christian Huygens depended on the
development of the escapement mechanism for the
pendulum created by Galileo.
His work in physics is well known and contin-
ues to be discussed in schools today. Recall his
experiment with two balls of unequal mass
dropped from the Tower of Pisa. He contended
that the time of descent of a ball was independent
of its mass. This was the exact opposite of what
Aristotle had proposed centuries before. Even
though Galileo was not the first person to make
this argument, he was able to demonstrate using
inclined planes and rolling balls that the principle
was indeed correct.

Atrium 23
Astronomy
Greek
astros- star
-nom (nemein) to dictate the laws of; knowledge,
usage, order
Study of planets, stars, and other objects in space.
Astrophysics
Greek
astros- star
-phusis- nature
The branch of astronomy that deals with the
physics of stellar phenomena.
Asymmetric
Greek
-summetros- of like measure
Unequal in size or shape; having no balance.
Asymptotic
Greek
-sumptotos intersecting
Refers to a line whose distance to a given curve
tends to zero; an asymptote may or may not inter-
sect its associated curve.
Asystole
Greek
-sustellein to contract
A life-threatening cardiac condition marked by
failure of the heart to contract.
Atactic
Greek
-taktos ordered
The type of orientation of the methyl groups on a
polypropylene chain in plastics—in this case ran-
dom orientation.
Ataxia
Greek
-taxis order
Lossoftheabilitytocoordinatemuscularmovements.
Athermancy
Greek
-thermos- combining form of “hot” (heat)
-ancy condition or state of
Impermeability to heat (i.e., no heat passing
through); the inability to transfer radiant energy.
Athermy
Greek
-y place for an activity; condition or state
A therapeutic treatment for certain diseases
involving no heat.
Atherosclerosis
Greek
athera- tumors full of pus, like a gruel
-skleros- hardening
A stage of arteriosclerosis involving fatty depos-
its (atheromas) inside the arterial walls.
Atmosphere
Greek
atmos- vapor
Mixture of gases that surrounds the earth.
Atoll
Sanskrit
antara interior
A nearly circular coral reef surrounding a shallow
lagoon.
Atom
Greek
-tomos (temnein) to cut, incise, section
A unit of matter, the smallest of an element, hav-
ing all the characteristics of that element and con-
sisting of a dense, positively charged nucleus
surrounded by an electron cloud.
Atonia
Greek
-tonos- tone, stretching, firm
plurals
Decrease in or lack of normal muscle tone, some-
times caused by prolonged paralysis.
Atrioventricular
atri- open area, central court, hall, entrance, or
main room of an ancient roman house
-ventricul- belly
-ar relating to or resembling
Relating to, involving, or resembling the area of
the atrium or ventricle of the heart; the atrioven-
tricular valve.
Atrium
Latin
atri- open area, central court, hall, entrance, or
main room of an ancient roman house

24 Atrophy
Chamber associated with the heart; upper chamber.
Atrophy
Greek
-trophos- (trophein) to nourish, food, nutrition;
development
A wasting away, deterioration, diminution, or
decrease in the size of a body organ, tissue, or part
owing to disease, injury, or lack of use.
Attenuate
Latin
-tenuis- thin
-ate of or having to do with
To make or become weaker; to reduce the size,
strength, or density of something; to become thin-
ner, weaker, less dense, or less virulent.
Auditory
Latin
audit- hearing, listening, perception of sounds
-ory tending to, serving for
Of or relating to hearing, the organs of hearing, or
the sense of hearing.
Auricle
Latin
auricula ear
An ear-shaped part of an organ.
Aurora
Latin
aurora dawn
Short for aurora australis or aurora borealis
(luminous bands or streamers of light visible in
night sky).
Aurous
Latin
aurum- gold
Of, relating to, or containing gold.
Austral
Latin
austr- south; south wind
or character of
Relating to or coming from the south.
Australopithecus
Latin
austral- southern; human race classification
-pithecus ape, apelike creatures
Extinct genus of African hominid family thought
to have lived between 4 and 1 million years ago.
Autecology
Greek
auto- self, same, spontaneous; directed from within
-oikos- home, house
bodies of knowledge
The ecology of an individual organism or species.
Autism
Greek
A psychiatric disorder of childhood characterized
by marked deficits in communication and social
interaction, preoc-cupation with fantasy, language
impairment, and abnormal behavior, such as repeti-
tive acts and excessive attachment to certain objects.
Autoclave
French
-clavis key (from the fact that it’s self-locking from
the pressurization)
A strong, pressurized, steam heat vessel, as used for
laboratory experiments, sterilization, or cooking.
Autogenous
Greek
Self-generated; produced independently. Coming
from the individual that it is growing in; a graft.
Autoionization
Greek
-ion- (ienai) to go; something that goes
-izein to cause or become
An ionization reaction between identical molecules.
Autolysis
Greek
-ly-(luein)toloosen,dissolve;dissolution,break
Self-acting disintegration of tissue by the release
of enzymes within the cells.
Autonomic
Greek
-nom (nemein) to dictate the laws of; knowledge,
usage, order
Functioning independently of the will; not under
voluntary control (e.g., as with most functions of
the nervous system).

Azimuth 25
Autopsy
Greek
-opsy examination
Examination of the organs of a body to determine
the cause of death.
Autosomal
Greek
-al of the kind of, pertaining to, having the form or
character of
Pertaining to or characteristic of an autosome.
Autosome
Greek
Any chromosome other than those that determine
the sex of an organism.
Autotherm
Greek
-thermos combining form of “hot” (heat)
An organism that regulates its body heat indepen-
dently of ambient temperature changes.
Autotoxin
Greek
-toxikos poison
Any harmful substance generated within the
body; something that is self-poisonous.
Autotroph
Greek
-trophos (trophein) to nourish; food, nutrition;
development
An organism that makes organic nutrients from
inorganic raw materials; any organism considered
to be a producer, capable of making its own food.
Autotrophic
Greek
-trophos- (trophein) to nourish; food, nutrition;
development
Relating to the process of synthesizing food
either by photosynthesis or by chemosynthesis.
Auxin
Greek
auxein to grow
Any of several plant hormones that regulate vari-
ous functions, including cell elongation.
Average
Arabic
awariyah damaged merchandise
A single value that summarizes or represents the
general significance of a set of unequal values.
Avian
Latin
avis bird
Of, relating to, or characteristic of birds.
Aviation
Latin
avis- bird
-ation state, process, or quality of
The art or science of flying, especially airplanes.
Avicide
Latin
avis- bird
Type of pesticide that controls populations of
birds considered to be pests.
Axiom
Greek
axios worthy
A universally recognized truth; self-evident, estab-
lished rule.
Axis
Latin
axis central
Any of the anatomical structures that lie centrally
or along a midcentral line within a body.
Axon
Greek
ax n axis
The usually long process of a nerve fiber that gen-
erally conducts impulses away from the body of
the nerve cell.
Azeotrope
Greek
-zein- to boil
-trope bend, curve, turn, a turning; response to a
stimulus
A mixture of two or more substances that has the
same composition in vapor state and liquid state.
Azimuth
Arabic
al- the
-samt way, path
In astronomy, the horizontal measurement of the
position of an object from north to east (clock-
wise) in degrees from a reference direction or a
celestial body (polaris).
o

Bacteremia
Greek
baktron- staff, rod
-haima- blood
plurals
Presence of bacteria in the blood.
Bacteria
Greek
baktron- staff, rod
plurals
Single-celled or noncellular spherical or spiral- or
rod-shaped organism without chlorophyll.
Bactericide
Latin
baktron- staff, rod
-cida cutter, killer, slayer.
Any chemical agent that kills bacteria
Bacteriophage
Greek
baktron- staff, rod
-phagein to eat
An ultra-microscopic filter-passing agent that has
the power to destroy bacteria and to induce bacte-
rial mutation.
Bacteriostat
Greek
baktron- staff, rod
-statos standing; stay; make firm, fixed, balanced
A class of antibiotics that prevents growth of bac-
terial cells.
Bacteriotherapy
Greek
baktron- staff, rod
Treatment of disease by introducing bacteria into
the system.
Bacteriotropic
Greek
baktron- staff, rod
stimulus
Having an affinity for bacteria; moving toward
bacteria.
Bacterium
Greek
baktron- staff, rod
A single-celled or non-cellular spherical or spi-
ral- or rod-shaped organism lacking chlorophyll
that reproduces by fission; important as a patho-
gen and for its biochemical properties; taxon-
omy is difficult (often considered a plant).
Bacteroid
Greek
baktron- staff, rod
-oid (oeid s) resembling, having the appearance of
Resembling bacteria in appearance or action.
Barometer
Greek
baro- weight, heavy; combining form meaning
“pressure”
e

Behavior 27
ing; to measure
An instrument for determining the weight or
pressure of the atmosphere, and hence used for
judging probable changes in the weather.
Baroreceptor
Greek
“pressure”
-reciepere- to receive
person that does something
In living tissue, a receptor end organ that responds
to pressure.
Base
Latin
basis fundamental ingredient, foundation
Any large class of compounds, including the
hydroxides and oxides of metals, having the abil-
ity to react with acids to form salts.
Basidiomycete
Latin/Greek
basid- foundation or base
-idion- (Greek) diminutive suffix
-muk t fungus
Any of a large group of fungi, including puff-
balls, shelf fungi, rusts, smuts, and mush-
rooms, that bear sexually produced spores on a
basidium.
Basidium
Latin
basid- foundation or base
Club-shaped organ involved in sexual reproduc-
tion in basidiomycete fungi (mushrooms, toad-
stools etc.) and bearing four haploid basidiospores
at its tip.
Basophile
Greek
basis- fundamental ingredient, foundation
preference for
A granulocytic white blood cell characterized by
cytoplasmic granules that stain blue when
exposed to a basic dye.
Batholith
Greek
bathy- deep, depth
-lith rock, stone
A mass of igneous rock that has melted and
intruded into surrounding strata.
Bathyal
Greek
bathy- deep, depth
or character of
Of or relating to a region of the ocean between
depths of 200 and 4,000 meters (660 and 13,000
feet).
Bedrock
Old English/Latin
bed- bed
-rocca rock, stone
The layer of solid rock beneath the gravel, soil,
and stone of the earth’s surface.
Behavior
Old English/French
be- to cause, make, affect
-havour to have
In biology, all of the responses to stimuli that an
organism is capable of displaying.
e
The Greek Language
Examining the origins of the languages of
Western cultures, we see that most had
their beginnings in the language of the
Greeks. Around the sixth century BC, the
ancient Greek culture flourished. Democ-
racy, cherished only by the wealthy, pro-
vided a political and social environment
for philosophers to ponder the nature of
the universe. Some put down in words
their interpretations of order and chaos.
Plato (427–347 BC), one of the most
famous Greek philosophers, metaphori-
cally linked science to politics by stating
that all things celestial were pure and
godly while earthly things were somehow
tarnished and corrupted. He referred to
planets as crystalline spheres and made an
analogy between the good and the sun:
“though the good itself is not essence but
still transcends essence in dignity and
surpassing power.” In Plato’s Allegory of
the Cave he speaks of shadows and captiv-
ity and the darkness. In many such ways
Plato and others advanced the sciences in
their time. Yet some would say they also
suppressed science and philosophy
through their belief that these endeavors
befit only the elite in Greek society.

28 Benthic
Benthic
Greek
benthos- bottom
Of the benthos, or bottom of the ocean or deep lake;
organisms existing at the bottom zone of the sea.
Beta (rays)
Greek
beta second letter of the Greek alphabet
Electrons or positrons that are emitted from a
radioactive substance.
Bias
French
biais slant
To apply a small voltage to.
Bicephalous
Greek
bi- two, twice, double, twofold
-cephalo- (kephalikos) head
Having two heads.
Bicuspid
Latin
-cuspis- sharp point, cusp
Having two points or cusps, such as a premolar
tooth.
Bidentate
Greek
-dentis- tooth
-ate to cause to be affected or modified by
To have two teeth or teethlike parts.
Bifurcation
Latin
-furca- fork
Thepointatwhichasplittingintotwopiecesoccurs.
Bilateral
Latin
-latus- side
or character of
Referring to two-sided symmetrical animals;
having identical parts on each side of an axis.
Bilirubin
Latin
b lis- bile
-ruber- red
A pigmented substance in the hemoglobin that
appears in the urine, darkening it and indicative of
liver or gallbladder disease.
Bimetallic
Latin
-metallon- mine, ore, quarry; any of a category of
electropositive elements from metallum
Relating to a substance composed of two differ-
ent metals that are bonded together.
Binary
Latin
bini- two at a time, two by two
Consisting of or involving two, as in binary fission.
Binocular
Latin
-ocul- of or relating to the eye
Having two eyes arranged to produce stereo-
scopic vision.
Binomial
Latin
-nom- (nemein) to dictate the laws of; knowl-
edge, usage, order
or character of
A taxonomic name consisting of two terms; bino-
mial nomenclature.
Bioaccumulation
Greek/Latin
bios- life, living organisms or tissue
-ad- to, a direction toward, addition to, near
-cumul re- to pile up
To accumulate in a biological system.
Bioaugmentation
Greek/Latin
-augere- to increase
Increasing the activity of bacteria that decompose
pollutants, a technique used in bioremediation.
Biocentrism
Greek
i
a

Biomimetics 29
-kentron- center, sharp point
The belief that all life—or even the whole uni-
verse, living or otherwise—taken as a whole, is
equally valuable, and that humanity is not the
center of existence.
Biodegradable
Greek
-degrade- to impair physical structure
-able capable, inclined to, tending to, given to
Capable of being decomposed by biological agents,
especially bacteria.
Biodiversity
Greek
-diverse- differing from another
-ity state, quality
The number and variety of organisms found within
a specified region.
Bioecologist
Greek
-eco- environment, habitat
-logist a person who studies
A specialist who studies the relation-ships of
organisms to their natural environments.
Bioenrichment
Greek/Latin/French
bios- (Greek) life, living
en- (Latin) in
-riche- (French) rich
-ment state or condition resulting from a (speci-
fied) action
Adding nutrients or oxygen to increase the micro-
bial breakdown of pollutants.
Biofuel
Various
-focus (fuel) hearth, fireplace
Any fuel derived from biomass, such as treated
municipal and industrial wastes and methane pro-
duced from renewable resources, especially plants.
Biogenesis
Greek
The biological principle that life originates or
arises from life, and not from nonliving things.
Biogeography
Greek
-geo- earth
-graphia (graphein) to write, record, draw, describe
The study of the geographical distribution of
organisms.
Biolith
Greek
-lithos stone or rock
A rock of organic origin.
Biologics
Greek
-logics talk, speak; speech; word
Agents, such as vaccines, that confer immunity to
diseases or harmful biotic stresses.
Biology
Greek
bodies of knowledge
The science of life and of living organisms,
including their structure, function, growth, ori-
gin, evolution, and distribution.
Biomass
Greek
-maza mass, large amount
The total amount or weight of living material in a
given area.
Biome
Greek
-oma community
A major region, such as continental grassland, that
has similar physical and climatological conditions.
Biomimesis
Greek
-minie- mimic, mime; imitate, act; simulation
In biology, the ability of an organism to mimic the
physical characteristics of another species.
Biomimetics
Greek
-minie- mimic, mime; imitate, act; simulation
-ic (ikos) relating to or having some character-
istic of
A branch of biology that uses information from
biological systems to develop synthetic systems.

30 Biopesticide
Biopesticide
Latin/Greek
-pestis- (Latin) plague, pestilance
Naturally occurring substances with pesticidal
properties.
Biopsy
Greek
-opsy examination
Selection of tissue removed from a living specimen.
Bioremediation
Greek
-re- again
-medi- middle
The process of using bacteria or other organisms
to “clean up” toxins in the environment.
Biosphere
Greek
-sphaire to surround
The thin outer shell of the earth and the inner lay-
ers of its atmosphere, the place where all living
systems are found.
Biotechnology
Greek
-tekhne- skill, systematic treatment
bodies of knowledge
The scientific manipulation of living organisms,
especially at the molecular genetic level, to produce
usefulproducts.Genesplicingandtheuseofrecom-
binant DNA(rDNA) are major techniques used.
Biotic
Greek
Living materials in an ecosystem; having some
characteristics of living organisms.
Biotoxin
Greek
-toxikos poison
Any toxic substance formed in an animal body and
demonstrable in its tissues or body fluids, or both.
Bipectinate
Latin
-pectin- comb
Feathery, with comblike branches or projections
growing out from both sides of the main axis
(applied mainly to insect antennae).
Bipedal
Latin
-ped- foot
or character of
An organism having two feet or capable of walk-
ing on two feet.
Biramous
Latin
-ramus- branch
Consisting of or having two branches, as the
appendages of an arthropod.
Bitumen
Latin
bit men a mineral pitch from the Near East
Any of various flammable mixtures of hydrocar-
bons and other substances, occurring naturally or
obtained by distillation from coal or petroleum,
that are components of asphalt and tar and are
used for surfacing roads and for waterproofing.
Bivalve
Latin
-valve leaf of a door
A mollusk that has a shell consisting of two
hinged valves.
Bladder
Latin
blaedre bladder
In biology, any sac or saclike organ that is capable
of distension as it fills with fluid.
Blastocoel
Greek
blastos- germ, bud
-koilos hollow
Cavity of the blastula.
Blastocyst
Greek
blastos- germ, bud
-kustis (cyst) sac or bladder that contains fluid
The modified blastula that is characteristic of pla-
cental mammals.
u

Bradycardia 31
Blastomere
Greek
blastos- germ, bud
-meros part
Name given to the early group of cells that result
from the fertilization and cleavage of an ovum.
Blastopore
Greek
blastos- germ, bud
-poros passage
The opening of the archenteron (the central open-
ing of the gastrula, which ultimately becomes the
digestive cavity).
Blastula
Greek
blastos- germ, bud
-ula diminutive
Early embryological stage of many animals; con-
sisting of a hollow mass of cells.
Blennogenic
Greek
blenno- mucus
-ic relating to or having some characteristic of
Producing or secreting mucus.
Blepharoplast
Greek
blepharon- eyelid
-plastos (plassein) something molded; to mold
A very small mass of cytoplasm at the base of a fla-
gellum, containing small amounts of chromatin.
Blood
Old English
bl d to thrive or bloom
The fluid consisting of plasma, cells, and plate-
lets that is circulated by the heart through the ver-
tebrate vascular system.
Bomb
Greek
bombos booming sound
A container capable of withstanding high internal
pressure.
Boreal
Latin
boreios coming from the north
Northern; of or relating to the north; the north wind.
Botany
Greek
botan - fodder, plants
-onuma name
The science or study of plants.
Botulism
Latin
botulus- sausage
A severe, sometimes fatal poisoning caused by
ingestion of food containing botulin and charac-
terized by nausea, vomiting, disturbed vision,
muscular weakness, and fatigue.
Boule
Latin
bulla bubble
A pear-shaped, aluminum-based synthetic mineral.
Bovine
Latin
bov- cow
Relating to, affecting, resembling, or derived
from a cow or bull.
Bowel
Latin
botulus sausage
The intestines; sometimes refers to the large
intestine.
Brachial
Greek
brackh n upper arm
or character of
Of or relating to the arm, forelimb, or wing of a
vertebrate.
Brachiopod
Greek
brakh n- upper arm
-pod foot
Any of various marine invertebrates of the phy-
lum Brachiopoda, having bivalve dorsal and ven-
tral shells enclosing a pair of tentacled, armlike
structures that are used to sweep minute food par-
ticles into the mouth; also called lampshell.
Brachiosaurus
Greek
brakh n- upper arm
-sauros lizard
Thegroupofverylarge,herbivorousdinosaursexis-
ting in the Jurassic and Cretaceous periods; nota-
ble features include long forelegs and a long neck.
Bradycardia
Latin/Greek
bradus- slow
-kard- heart; pertaining to the heart
plurals
o
e
io
i
i

32 Breeds
Slower-than-normal heart rate in humans, usually
considered to be less than 60 beats per minute.
Breeds
Old English
bredan to breed
Variations within the same species that are capa-
ble of reproducing with one another; phenotypic
modifications within a group.
Brevis
Latin
brevis brief
An anatomical term meaning “short,” usually
associated with skeletal muscle.
Brittle
Old English
brytel to shatter
Likely to break, snap, or crack.
Bronchitis
Greek
bronkhos- windpipe
Chronic or acute inflammation of the mucous
membrane of the bronchial tubes.
Bronchogenic
Greek
bronkhos- windpipe
Originating in the bronchi or having its origin in
the bronchus.
Bronchomalacia
Greek
bronkhos- windpipe
The degeneration or softening of the trachea as a
result of some disorder.
Bronchus
Greek
bronkhos- windpipe
-us singular
Main branch of the windpipe.
Bryophyte
Greek
bruein- to swell or teem
-phyte plant
Any of a division of nonvascular plants that lack
vascular tissue, including mosses and liverworts.
Bryozoan
Greek
bruon- moss
-zôion living being
Any of various small aquatic animals of the phy-
lum Bryozoa that reproduce by budding and form
mosslike or branching colonies permanently
attached to stones or seaweed; also called moss
animal or polyzoan.
Buoyancy
Dutch/Latin
buoy- to float
-ancy condition or state of
The tendency of a body to float or to rise when
submerged in a fluid

Cadaver
Latin
cadere- to fall or die
-er one that performs that action
A corpse or dead body.
Caddisfly
Old English
cadace- cotton wool (refers to the tube in which
the larva lives)
-fl oge fly
Any of various insects with four hairy wings,
chewing mouthparts, and long antennae; aquatic
larvae.
Caldera
Late Latin
caldaria cooking pot
Large crater formed when the sides of a volcanic
cone collapse.
Calendar
Latin
kalendae- account book
Any of various systems of reckoning time in
which the beginning, length, and divisions of a
year are defined.
Calibrate
Arabic
qalib- shoemaker’s last
To check, adjust, or determine by comparison
with a standard.
Calomel
Greek
kalos- beautiful
-melas black
A tasteless compound, Hg2Cl2, used as an
insecticide.
Calorie
Latin
calor- heat
Any of several approximately equal units of heat,
each measured as the quantity of heat required to
raise the temperature of 1 gram of water by 1
degree Celsius from a standard initial temperature.
Calorimeter
Latin/Greek
calor- heat
-meter(metron)instrumentormeansofmeasuring;
to measure
An apparatus for measuring quantities of absorbed
or evolved heat typically generated in a reaction.
Calorimetry
Latin
calor- heat
-metria process of measuring
Measurement of the amount of heat released or
absorbed during a chemical reaction.
Calving
Middle English
calve- calf
-ing the act or action of
The process by which a block of a glacier breaks
off and falls into the sea to form an iceberg.
e

34 Calyx
Calyx
Greek
kalyx cup
The outer whorl of a flower, the sepals.
Cambium
Latin
cambiare- to exchange
Plant tissue commonly present as a thin layer that
forms new cells on both sides; located either in
vascular tissue (vascular cambium), forming
xylem on one side and phloem on the other, or in
cork (cork cambium or phellogen).
Camouflage
French/Latin
camoufler- to disguise
Concealment by means of disguise or protective
coloring.
Campodeiform
Greek
campo- caterpillar, bend, curve
-dei- god, deity, divine nature
-form having the form of
Applied to insect larvae, grublike, flattened, and
elongated with well-developed legs and anten-
nae; many beetle larvae are of this type, as are
those of the lacewings.
Canaliculus
Latin
can lis- conduit
-us thing
Very small channels or ducts in the body; nor-
mally associated with the Haversian system of
compact bone.
Cancer
Latin
cancer crab
A pathological condition marked by the growth
and proliferation of neoplastic cells.
Candle
Latin
candela candle
A unit of light intensity equal to the amount of
light emitted from a standard source such as a
candle or an incandescent light.
Canine
Latin
cani- dog
An animal of the family Canidae; belonging to or
characteristic of a dog.
Capacitor
Latin
capacitas- spacious
-or person or thing that does something
An electrical circuit element used to store charge
temporarily.
Capelin
Latin
cappa- cap or cape
-lin small or little
A small food fish of the smelt family, found in
north Atlantic coastal waters.
a
a
The Heiki Warriors and Natural Selection
Each year on April 24, fishermen who are
descendants of the Heike warriors com-
memorate the last battle of the war between
the Heike and Genji samurai clans. On this
day, the Heike clan succumbed to its final
defeat. The naval battle of Danno-ura was
the last stand for this noble clan.
The Heike fought gallantly against an
opposing force that greatly outnumbered
them. In the end, the survivors, rather than
being taken alive, jumped from their ships
and committed mass suicide. Among them
was their emperor, a seven-year-old boy
named Antoku.
The story might have ended there, but
for a small group of handmaidens who
remained on shore that day. After the war,
they lived among the fishermen of the vil-
lage and bore children.
Over the centuries, the celebration has
grown into a legend. The story has it that
the Heiki samurai still wander at the bottom
of the sea, as evidenced by the many crabs
there with markings of what appears to be
the face of a samurai.
This is a wonderful example of natural
selection. The fishermen of the Danno-ura
cast their nets into the inland sea and bring
up thousands of crabs. Among them is one
with markings vaguely resembling a face
on its carapace. The fishermen believe this
crab to be sacred and therefore throw it
back. The process is repeated countless
times. The crabs breed and the likeness of a
face is selected for because the crabs bear-
ing it are not harvested. Thus, over time,
humans preferentially selected a pheno-
type, the face of a samurai, to predominate
among the population.

Cardiac 35
Capillary
Latin
capill- hairy
-ary pertaining to
As fine or minute as a hair; having a very small
bore, as a tube.
Capsid
Latin
cap- catch, seize, take hold of, contain, take,
hold
-sid state, condition; having, being, pertaining to,
The coating of a protein that encloses the nucleic
acid core of a virus.
Capsule
Latin
capsa- box
-ule little, small
A sticky layer that surrounds certain bacteria.
Carapace
Spanish
carapacho covering
The fused chitonous exoskeleton of various inver-
tebrates such as crustaceans.
Carbohydrate
French
carbo- carbon
-hydr- solid compound containing water molecules
Any of a group of organic compounds produced by
photosynthetic plants, including sugars, starches,
celluloses, and gums, and that serves as a major
energy source in the animal diet.
Carbonation
Latin
carbonate- to charge with carbon dioxide gas
Saturation with carbon dioxide gas.
Carcinogen
Greek
karkinos- crab, cancer
A substance that induces cancer. Carcinogens are
more likely to affect tissues where rapid cellular
reproduction takes place.
Carcinoma
Greek
karkinos- crab, cancer
A malignant growth or tumor.
Cardiac
Greek
kard- heart; pertaining to the heart
-ac pertaining to
Referring to the heart.
Impregnating Water with Fixed Air
Joseph Priestley was born in Birstall parish
near Leeds, England, in 1733. He was a
man of many interests. He was persecuted
for his interest in civil rights, government,
religion, and philosophy, but it was his
sympathetic view of the French people dur-
ing the French Revolution that led to rumors
and conspiracy against him. His home, labora-
tory, and church in Birmingham were burned
to the ground in 1791. He later fled to the
United States and took up residence in
Northumberland County, Pennsylvania, where
he died in 1804.
In 1772 Dr. Joseph Priestley published a
paper titled “Impregnating Water with Fixed
Air.” Here we have the beginnings of car-
bonated beverages. Priestley experimented
with the gas given off by fermenting beer
and soon discovered some very interesting
characteristics of his collected gas. For
example, he learned that the unknown gas
was heavier than air, for it remained in the
opened containers and did not mix with the
ambient air. By performing a common sci-
ence experiment that is duplicated in most
secondary schools across the United States,
he came to discover that this gas would
extinguish flaming wood chips. The gas that
Priestley called “fixed air” was also referred
to as “mephitic air” by Joseph Black.
Dr. Priestley’s work with “fixed air” led
him to perform an experiment where he
placed a vessel of water in the gas lingering
about the fermented beer. He found that
some of the gas dissolved in the standing
water, producing a rather tasty beverage,
which we know as soda water.
Dr. Priestley’s work with gases further
led him to the “discovery” of oxygen in
1774. Although oxygen had been identified
earlier by Michal Sedziwoj in the sixteenth
century and later by Carl Wilhelm Scheele
in 1772, Joseph Priestley was the first to
publish his results on the gas in 1775, two
years before Scheele published his own
work. Therefore, Dr. Priestley is commonly
credited with the discovery of oxygen.

36 Cardialgia
Cardialgia
Greek
Localized pain in the region of the heart.
Cardiology
Greek
bodies of knowledge
The study of the heart and its actions and diseases.
Cardiomalacia
Greek
The softening and degeneration of the walls of the
heart, usually because of a disorder.
Cardiomyopathy
Greek
-myo- muscle
-patheia disease; feeling, sensation, perception
A disease or disorder of the heart muscle, espe-
cially one of unknown or obscure cause.
Cardiovascular
Greek
-vascul- small vessel
Relating to the heart and the blood vessels of the
circulatory system.
Carnivore
Latin
caro- meat
-vorare to devour
Any animal that kills and feeds on other animals.
Carotenoid
Latin/Greek
carota- carrot
Any of a class of yellow to red pigments, includ-
ing the carotenes and the xanthophylls.
Carotid
Greek
karoun- to put to sleep, plunge into sleep or stupor,
stupefy
-id state or condition; having, being, pertaining to,
Either of the two major arteries, one on each side of
the neck, that carry blood to the head; their com-
pression was believed to cause unconsciousness.
Carpal
Greek
carpus- wrist; that which turns
or character of
A bone of the wrist; of or relating to the wrist.
Carpel
Greek
karpos fruit
One of the structural units of a pistil, representing
a modified, ovule-bearing leaf.
Cartilage
Latin
cartilago- cartilage
Various tissues containing cartilaginous cells and a
matrix composed of water and fibers; it is com-
monly found in movable joints, the external ear, and
the nose, and is the precursor of numerous bones in
the human body.
Cartography
Greek
khartes- map, chart, paper
The science of map or chart making.
Catabolism
Greek
kata- down, downward; under, lower; against;
entirely, completely
-ism state, condition, or quality
Decomposition of larger molecules within cells.
Catadromous
Greek
-dramein/dromos to run
Refers to fish that migrate from freshwater to the
ocean to spawn.
Catalyst
Greek
-ly- (luein) to loosen, dissolve; dissolution, break
A substance that enables a chemical reaction to
proceed, usually at a faster rate or under different
conditions than are otherwise possible.
Cataract
Greek
e
a

Centripetal (force) 37
-arassein to strike
Opacity of the lens or capsule of the eye, causing
impairment of vision or blindness.
Catenation
Latin
catena- connection of links or union of parts, as
in a chain; a regular or connected series
Bonding of atoms of the same element into chains
or rings.
Cathode
Greek
-hod s way or road
A negatively charged electrode; an electrolytic
cell or a storage battery.
Cation
Greek
-ion (ienai) to go; something that goes
An ion or group of ions having a positive charge and
movingtowardthenegativeelectrodeinelectrolysis.
Caudal
Latin
caud- tail
or character of
Constituting, belonging to, or relating to a tail.
Cauterization
Latin
cauter- heat
-ization action, process, or result of doing or making
The process of searing a damaged part of the body
by the use of heat or a chemical.
Cecum
Latin
caecus blind
A blind pouch that serves as the entrance to the large
intestine.
Ceilometer
Latin
caelum- sky, heaven
to measure
A device that measures the height of cloud layers.
Celestial
Latin
caelum- sky, heaven
-ial (variation of -ia) relating to or characterized by
Of or relating to the sky or the heavens; planets
are celestial bodies.
Cell
Latin
cella chamber
The smallest unit of a living thing that is capable
of carrying out all life processes.
Cellulose
Latin
cellula- little cell
-ose sugar
Colorless, insoluble, indigestible polysaccharide
that makes up the cell wall.
Celsius
Celsius Swedish scientist (Anders Celsius) who
introduced the scale also known as centigrade for
measuring temperature
Scale of temperature in which the range from the
freezing to the boiling of water is divided into 100
degrees (freezing being 0 and boiling being 100
degrees).
Cenozoic
Greek
kainos- new
-zoe- life
Division of geologic time that lasted 65 million
years after the Mesozoic.
Centipede
Latin
centi- one hundred
-pede feet
Wormlike arthropods in the class Chilopoda.
Centrifuge
Greek/Latin
kentron- center, sharp point
-fugere to flee
Adeviceforseparatingcomponentsofdifferentden-
sities contained in liquid by spinning at high speed.
Centriole
Greek
-ole little
Organelle associated with spindle formation dur-
ing mitosis in animal cells.
Centripetal (force)
Greek/Latin
-petal (petere) moving toward; to seek
The force that opposes the inertia of a body and is
required to keep a body in a circular motion.
o

38 Centroid
Centroid
Greek
The point in a system of masses each of whose
coordinates is a weighted mean of coordinates of
the same dimension of points within the system.
Centromere
Greek
-mere part of
The area of the chromosome, usually in the cen-
ter, where sister chromatids are attached.
Centrosome
Greek
A small region of cytoplasm adjacent to the nucleus
that contains the centrioles and serves to organize.
Cephalic
Greek
cephalo- (kephalikos) head
Of or relating to the head; anatomical term for
“head.”
Cephalization
Greek
Concentration of sensory and nervous systems in
one area of the body, which is called a “head.”
Cephalopod
Greek
-poda foot
Group of mollusks having a large head, large
eyes, prehensile tentacles, and, in most species,
an ink sac for protection.
Cephalothorax
Greek/Latin
-thorax breastplate, chest
The anterior section of arachnids and many crus-
taceans, consisting of the fused head and thorax.
Cepheid
Greek
A variable star that scientists can use to determine
how distant a galaxy, or star cluster, is because of
its highly regular pulsation.
Ceraceous
Latin
cer- wax
Waxen, like wax; covered with or resembling wax.
Cercaria
Greek
kerkos- tail
-aria like or connected with
Tadpole-like juveniles of trematodes (flukes).
Cerebellum
Latin
cerebr- of or relating to the brain or cerebrum
-bellum war
A region of brain that lies posterior to the pons
and is responsible for voluntary muscular move-
ment, posture, and balance.
Cerebral
Latin
or character of
The largest part of the brain, consisting of two lobes,
the right and left cerebral hemispheres. The cere-
brum controls thought and voluntary movement.
Cerebromalacia
Greek
Theabnormalsofteningofthecerebralparenchyma.
Cerebroside
Latin
-ide group of related chemical compounds
A group of lipids that occur most abundantly in
the membranes of nerves and brain cells.
Cerussite
Latin
c russa- a white lead pigment, sometimes used in
cosmetics
Native lead carbonate; a mineral occurring in
colorless, white, or yellowish transparent crys-
tals, with an adamantine, and that is massive and
compact.
Cervical
Latin
cervic- stem of cervix
or character of
Relating to the neck or any part of the body that
resembles a neck.
e
e

Chilopoda 39
Cetacean
cetu- whale
Order of marine mammals including whales, dol-
phins, and porpoises.
Chaetotaxy
Greek
chaeto- spine, bristle; long, flowing hair
-taxy arrangement, order; put in order
The arrangement of the bristles or chaetae on an
insect, especially important in the classification of
the Diptera, Collembla, and several other groups.
Chalcopyrite
Greek
khalkos- copper
-p r- fire
A yellow mineral, essentially CuFeS2, that is an
important ore of copper; also called copper pyrite.
Charge
Latin
carrus Gallic type of wagon.
The intrinsic property of matter responsible for
all electric phenomena—in particular, for the
force of the electromagnetic interaction—
occurring in two forms, arbitrarily designated
negative and positive.
Chatoyant
Latin
cattus- cat
-antperforming,promoting,orcausingaspecified
action
A gemstone (cat’s-eye) having the capacity of
changing its luster or color because of the way nar-
row bands or streaks of light reflect off its surface.
Cheilostomatoplasty
Greek
cheil- claw, lip, edge, or brim
-stomat- mouth, opening
-plastos- (plassein) something molded; to mold
-y place for an activity, condition, or state
Plastic surgery of the lips and mouth.
Chelicera
Greek
khele- claw
-keras horn
One of a pair of the most anterior head appendages
on members of the subphylum Chelicerata.
Cheliped
Greek
khele- claw
-ped foot
A pincerlike claw of a crustacean or arachnid,
such as a lobster, crab, or scorpion.
Chemical
Greek
khemeia- chemical; alchemy
or character of
A substance composed of chemical elements or
one produced by or used in chemical processes.
Chemistry
Greek
The science of the composition, structure, proper-
ties, and reactions of matter, especially of atomic
and molecular systems.
Chemoautotroph
Greek
-auto-self,same,spontaneous;directedfromwithin
development
Organism that obtains its nourishment through
oxidation or inorganic chemical compounds.
Chemoheterotroph
Greek
-heteros- different
development
Any of a group of bacteria that, in addition to deriv-
ing energy from chemical reactions, synthesize all
necessary organic compounds from carbon dioxide.
Chemotherapy
Latin
A treatment for cancers that involves administer-
ing chemicals that are toxic to malignant cells.
Chiasma
Greek
kh azein to mark with an X
In anatomy, the crossing or intersecting of two
tracts; the optic chiasma. In genetics, the point of
contact between paired chromatids.
Chilopoda
Greek
kheilos- lip
-poda foot
A very large group of insects that includes centi-
pedes; they are characterized by having elongated
legs attached to each segment, with a pair of legs
u
i

40 Chimera
in the thorax that serve as fangs, and by having
very powerful mouthparts.
Chimera
Greek
chimaira she-goat
An organism composed of two or more geneti-
cally distinct tissues, such as one that is partly
male and partly female, or an artificially produced
individual having tissues of several species.
Chiropractic
Greek
chir- hand; pertaining to the hand or hands
-praktikos- practical
A system of therapy in which disease is consid-
ered the result of abnormal function of the ner-
vous system; treatment usually involves
manipulation of the spinal column and other
body structures.
Chiroptera
Greek
chir- hand; pertaining to the hand or hands
-pteron wing
Order of flying mammals (bats).
Chloragogen
Greek
chlor- the color green, yellow-green, or light green
-agogos- a leading, a guide
Modified greenish or brownish peritoneal cells
clustered around the digestive tract of certain
annelids; they apparently aid in the elimination of
nitrogenous wastes and in food transport.
Chlorofluorocarbon
Greek
-fluere- chemical element; to flow
-carbo- coal, charcoal
-on a particle
Anyofseveralsimplegaseouscompoundsthatcontain
carbon,chlorine,fluorine,andsometimeshydrogen.
Chloroform
Greek/Latin
-formyl [-form(ic) found in ants + yle wood, matter]
A clear, colorless, sweet-smelling liquid used in
refrigerants, propellants, and resins; as a solvent;
and sometimes as an anesthetic.
Chlorophyll
Greek
-phullon leaf
Green pigment found in photosynthetic organ-
isms that is capable of absorbing light and con-
verting it to energy from oxidation and reduction
in the photosynthesis of carbohydrates.
Chloroplast
Greek
Chlorophyll-containing plasmid found in algal
and green plants.
Choanoblast
Greek
choane- funnel
-blastos bud, germ cell
A cell that gives rise to one or more collar bodies,
especially in the sponge class Hexactinellida.
Choanocytes
Greek
choane- funnel
One of the flagellate collar cells that line the cav-
ities and canals of sponges.
Cholecystectomy
New Latin
khole- bile, gall
-kustis- (cyst) sac or bladder that contains fluid
Surgical excision of the gallbladder.
Cholelith
Greek
khole- bile, gall
-lith stone, rock
A small, hard pathological concretion composed
chieflyofcholesterol,calciumsalts,andbilepigments,
formedinthegallbladder orinabileduct;gallstone.
Cholesterol
Greek
khole- bile, gall
-steros- solid
-ol chemical derivative
A white crystalline substance found in animal tis-
sues and various foods that is normally synthesized
by the liver and is important as a constituent of cell
membranes and a precursor to steroid hormones.
Chondroblast
Greek
khondros- granule, cartilage
Animmaturecartilagecellfoundingrowingcartilage.
Chondroclast
Greek

Chronometry 41
-klastos break, break in pieces
A cartilaginous cell involved with the reabsorb-
tion of the cartilaginous matrix.
Chondrocyte
Greek
A mature cartilage cell that can be found in the
lacunae of the cartilaginous matrix.
Chondromalacia
Greek
Softening of any cartilage, usually because of a
physiological disorder.
Chordate
Greek
khorde- gut, string of a musical instrument
Of, pertaining to, or belonging to the phylum
Chordata or to a chordate subphylum; animals
having at least at some stage of development of a
notochord, a dorsally situated central nervous
system, and gill clefts.
Choroid
Greek
khorion- afterbirth
The very dark brown vascular coat found between
the sclerotic coat and the retina of the eye.
Chromatics
Greek
khromat- color
The scientific study of color.
Chromatid
Greek
khromat- color
One of the two identical threadlike filaments of a
chromosome.
Chromatin
Greek
khromat- color
A complex of nucleic acids and proteins in the cell
nucleus that stains readily with basic dyes and con-
denses to form chromosomes during cell division.
Chromatography
Greek
khromat- color
Analysis of mixtures of chemical compounds by
passing solutions of them through an absorbent.
Chromogen
Greek
khromat- color
A substance capable of conversion to a pigment
or dye.
Chromophore
Greek
khromat- color
-phore bearer, carrier
A chemical group capable of selective light
absorption resulting in the coloration of certain
organic compounds.
Chromosome
Greek
khromat- color
Any one of the threadlike nucleoprotein struc-
tures in the nucleus of the cell that function in the
transmission of genetic information.
Chromosphere
Greek
khromat- color
An incandescent, transparent layer of gas lying
above and surrounding the photosphere of the sun.
Chronic
Greek
khronos- time
-ic (ikos) relating to or having some characteristic
of
Lasting a long time, long-continuing, lingering,
inveterate (as diseases).
Chronobiology
Greek
khronos- time
bodies of knowledge
The scientific study of the effect of time on living
systems.
Chronogram
Greek
khronos- time
-gram something written or drawn; a record
The record produced by a chronograph.
Chronometry
Greek
e

42 Chrysalis
khronos- time
The scientific measurement of time.
Chrysalis
Greek
khr sallid gold-colored pupa of a butterfly
The protective stage of development in moths and
butterflies in which the pupa is contained in a
tough case or cocoon.
Chyle
Greek
chylos juice
A milky fluid containing emulsified fat and other
products of digestion formed from the chyme in
the small intestine and conveyed by the lacteals
and the thoracic duct to the veins.
Cilia
Latin
cili- a small hair
plurals
Small hairlike projections that help ciliates move,
sense their environment, and collect food.
Ciliate
Latin
cili- a small hair
Any of a group of animal-like protists that are
characterized by having cilia.
Circadian
Latin
circum- around
-diurnus- day
Designating physiological activity that occurs
approximately every twenty-four hours, or the
rhythm of such activity.
Circuit
Greek
kirkos circle
A set of electronic components that perform a
particular function in an electronic system.
Circular
Latin
circulus- to make circular
Referring to a path that follows the shape of a
circle.
Circulation
Latin
circulus- to make circular
Movement or flow through a circle or circuit.
Eratosthenes’ Shadows
“Let none enter here who are ignorant of geome-
try.” This quote was inscribed above the entrance of
Plato’s school, illustrating the importance of math-
ematics to the early philosopher-scientists of
Greece and Egypt. Without knowledge of geome-
try, we’d be left with many elegant theories, per-
haps, but no reasoned explanations. Plato, though
not a mathematician, understood this.
This brings us to Eratosthenes (276–194 BC),
born in what is now Libya. A man of considerable
influence, Eratosthenes was a mathematician,
astronomer, geographer, poet, historian, and phi-
losopher. He studied and worked, probably as a
director, in the Great Library of Alexandria. It is
here he read that at noon every June 21, the sun
cast no shadow in the Egyptian village of Syene.
And on that same day at the same hour, the full
face of the sun was reflected in the waters of the
village’s deep well. To even the uninformed
observer, it was obvious that the sun was directly
overhead.
Perhaps out of curiosity or an attempt to vali-
date the account of Syene, Eratosthenes, using
only a stick placed in the sand at Alexandria (a
considerable distance north of Syene), made the
observation that at noon of June 21, a rather
lengthy shadow was cast. Undoubtedly, Era-
tosthenes asked himself what possibly could
account for such a phenomenon. If the earth were
flat, like the maps, then the shadows should be the
same length—provided, of course, that the sun was
a considerable distance from the earth. Or could
the earth be a sphere, and not flat at all? Knowing
that the distance from Alexandria to Syene was
about 800 kilometers, and observing and calculat-
ing the difference between the shadow lengths at
the two locations, Eratosthenes calculated that the
degree of the angle where the sticks would inter-
sect deep within the earth was probably close to 7
degrees. Having that bit of information, he was
able to determine the circumference of the earth. If
the opposite side of a 7-degree angle is 800 kilo-
meters, and there are 360 degrees in a circle, the
resulting circumference is around 40,000 kilome-
ters. He was pretty accurate for someone using
only his intellect and no technology.
u

Clinic 43
Circumcision
Latin
circum- in a circle; around, about, surrounding
-caedere- to cut
The act of cutting around; the cutting and removal
of all of the prepuce in males or the prepuce, cli-
toris, or labia in females.
Circumference
Greek
-ferre to carry
The boundary line of a circle, or the length of
such a boundary.
Circumlunar
Latin
-lunar moon, light, shine
Revolving around or surrounding the moon.
Cirque
French (from Latin)
circus circle
A steep, hollow, bowl-shaped basin occurring at
the upper end of a mountain valley.
Cirrhosis
Greek
kirrhos- tawny yellow
A chronic disease of the liver characterized by the
replacement of normal tissue with fibrous tissue,
the loss of functional liver cells, and an abnormal
yellowish appearance.
Cirrus
Latin
cirro hair; wispy
High clouds with a base of 6,000 meters.
Cistron
Latin
cist- to cut
-on a particle
Segment of DNA that is required in order to syn-
thesize a complete polypeptide chain.
Cladistics
Greek
klados- branch or sprout
A system of arranging taxa to reflect phylogenetic
relationships.
Cladogram
Greek
klados- branch or sprout
-gramma letter
A branching diagram showing the pattern of shar-
ing evolutionarily derived characters among spe-
cies or higher taxa.
Clastic
Greek
klastos- broken
Sedimentary rock formed by fragments of previ-
ously existing rock.
Clavicle
Latin
cl vis- key (from its shape)
One of two slender, key-shaped bones located
be-tween the scapula and the manubrium of the
sternum.
Cleavage
Middle English
cleave- to split or separate
Splitting or separation along a natural Zline of
division.
Clepsydra
Greek
kleps- to steal
-hudor water
An ancient device used for measuring time by the
dripping of water from a graduated vessel.
Climate
Greek
klime- slope
General conditions of temperature and precipita-
tion for an area over a period of time.
Clinarthrosis
Greek
klinein- to lean; sloping
-arthr- pertaining to the joints
-osis process, condition, or state of
Abnormal deviation in the alignment of the bones
at a joint.
Cline
Greek
klinein to lean; sloping
A continuous series of differences in structure or
function exhibited by the members of a species
along a line extending from one part of their
range to another.
Clinic
Greek
klinikos- pertaining to a bed or couch
a
a

44 Clinician
A clinical lecture; examination of patients before
a class of students; instruction at the bedside.
Clinician
Greek
An experienced practitioner such as a nurse, phy-
sician, or psychologist as opposed to someone
involved in research.
Clinicopathologic
Greek
-pathos- feeling, sensation, perception; suffering,
disease
-logic talk, speak; speech; word
Pertaining both to the symptoms of a disease and
to its pathology.
Clinocephaly
Greek
-cephaly (kephalikos) head
Congenital flatness or concavity of the vertex of
the head.
Clinodactyly
Greek
klinein- to lean; sloping
-dactylos finger, toe
Permanent lateral or medial deviation or deflec-
tion of one or more fingers.
Clinography
Greek
A system of graphical representations of the tem-
perature, symptoms, and pathological manifesta-
tions exhibited by a patient.
Clinoid
Greek
-oid (oeid s) resembling, having the appearance o
Bed-shaped, as the clinoid processes of the sphe-
noid bone.
Clinostatism
Greek
The condition of lying down or being in the hori-
zontal position.
Cliseometer
Greek
klisis- inclination
to measure
An instrument for measuring the angle that the
pelvic axis makes with the spinal column.
Clitellum
Latin
clitellae- packsaddle
A thickened glandular section of the body wall of
some annelids that secretes a viscid sac in which
the eggs are deposited.
e
How Do You Discover the Invisible?
It has been said that Empedocles of
Agrigentum (ca. 490–430 BC), a mystic,
poet, and physician, was so self-absorbed
that he considered himself a god and was
perhaps considered divine by others.
Empedocles postulated that all matter is
made up of four “roots”: water, earth, fire,
and air. He declared that love (phila) was
the force that held these roots together and
that discord (neikos) was the force at work
to keep them apart.
We know air to be an invisible medium,
but to the ancient Greeks, the wind was the
breath of the gods. It had no substance and
no tangible qualities. How, then, could
Empedocles prove the existence of air?
One of the rare Greek scientists who actu-
ally did experiments, Empedocles used a
clepsydra, a common household ladle or
“water clock,” for his test. A clepsydra was
a vessel with markings and one or more
small holes at its base to allow water to drip
out. The top of the vessel had a strawlike
tube attached. When Empedocles filled the
clepsydra with water, it dripped out the bot-
tom. But when he put his finger over the
opening of the tube at the top of the vessel,
the water stopped dripping. When he tried
filling the vessel with his thumb over the
opening of the tube, as he submerged the
clepsydra, no water could enter the vessel
through the other end. What could be caus-
ing this? Empedocles argued that some-
thing invisible but with substance (matter)
filled the void in the vessel. If it could not
be moved out, then nothing could take its
place. Hence air, though invisible, exists
and has substance.

Coadunation 45
Clitoris
Greek
kleitoris clitoris
An organ of very sensitive tissue located just
anterior to the urinary meatus.
Cloaca
Latin
cloa'cae drain
A common passage for fecal, urinary, and repro-
ductive discharge in monotremes, birds, and
lower vertebrates.
Clone
Greek
kl n young shoot or twig
A cell, group of cells, or organism that is
descended from and genetically identical to a sin-
gle common ancestor, such as a bacterial colony
whose members arose from a single original cell.
Clonogenic
Greek
kl n- young shoot or twig
An organism arising from or consisting of a clone
of cells.
Clupeine
Latin
clupea- herring, small fish
A protamine obtainable from the spermatozoa of
the herring.
Cnemitis
Greek
kn m - leg
Inflammation of the tibia.
Cnemoscoliosis
Greek
kn m - leg
-scoli- curvature; curved, twisted, crooked
A lateral bending of the lower limb.
Cnicus
Greek
kn kos- safflower
-us thing
A genus of European herbs of the family
Compositae.
Cnidaria
Greek
kin’ dh- to sting; nettle
plurals
Phylum consisting of organisms with special
stinging cells.
Cnidoblast
Greek
The epidermal cells of coelenterates that contain the
nematocysts, especially numerous on the tentacles.
Cnidocil
Greek
-cilium hair
Triggerlike spine on a nematocyst.
Cnidocilium
Greek
-cili- a small hair
A bristle-like process at one end of a cnidoblast,
which, when stimulated, triggers the discharge of
the nematocyst.
Cnidocytes
Latin
Stinging cell used by cnidarians to stun their prey.
Coacervate
Greek
co- together, with
-acerv re- to heap
The viscous phase separating from a colloid-
containingsysteminthephenomenonofcoacervation.
Coacervation
Greek
co- together, with
-acerv re- to heap
The separation of a mixture of two liquids, one or
both of which are colloids, into two phases; one
(the coacervate) contains the colloidal particles,
and the other is an aqueous solution (e.g., as when
gum arabic is added to gelatin).
Coadunation
Latin
co- together, with
-unus- one
Union of dissimilar substances in one mass.
o
o
e e
e e
e
a
a

46 Coagulate
Coagulate
Latin
co- together, with
-agulum- to condense; to drive
To cause the transformation of a liquid into a soft,
semisolid, or solid mass.
Coalescence
Latin
co- together, with
-alescere- to come together or grow
The act of growing together; the act of uniting.
Coccidium
Greek
co- together, with
-kokkos- berry, grain, seed
In former systems of classification, a genus of
coccidians, the organisms of which have been
assigned to other genera.
Cochlea
Greek
kokhlias snail
A spiral-shaped cavity of the inner ear that con-
tains nerve endings essential for hearing.
Codominance
Latin
co- together, with
-domo- house, home
-ance state, quality
In genetics, the tendency of certain (dominant)
alleles to mask the expression of their corre-
sponding (recessive) alleles.
Codominant
Latin
co- together
-dominae to rule
Referring to an equal degree of dominance of two
alleles or traits fully expressed in a phenotype.
Codon
Latin
cod-acodeoflaws;awritingtablet;anaccountbook
-on subatomic particle
A group of three nucleotides that specifies the
addition of one of the twenty amino acids during
translation of an mRNA into a polypeptide. Strings
of codons form genes, and strings of genes form
chromosomes.
Coefficient
Latin
co- together, with
-efficiens- efficient
-ent causing an action; being in a specific state;
within
Number that serves as a measure of some prop-
erty or characteristic; numerical factor by which
the value of another is multiplied.
Coelenterata
Greek
koilos- hollow cavity
-enteron intestine
Former name for a phylum of marine inverte-
brates including sea anemones, hydras, jellyfish,
and corals, which are now assigned to the phylum
Cnidaria.
Coelenteron
Greek
-enteron intestine
Internal cavity of a cnidarian; gastrovascular cav-
ity; archenteron.
Coelom
Greek
koilos hollow cavity
The epithelium-lined space between the body
wall and the digestive tract of metazoans above
lower worms.
Coelomoduct
Greek
-ductus leading
A duct that carries gametes or excretory products
(or both) from the coelom to the exterior.
Coenocytic
Greek
coeno- shared
-kutos- (cyto) sac or bladder that contains fluid
Multinucleate, with nuclei not separated by cross
walls.
Cohesion
Latin
co- together, with
-haerere- to stick together
The binding together of like molecules.
Cohesive
Latin
co- together, with
-haerere- to stick together
Holding the particles of a homogeneous body
together.

Comet 47
Coitus
Latin
co- together, with
- re to go, come
The sexual union of a male and female.
Colchicine
Latin
kolkhikon- meadow saffron
Poisonous, pale-yellow alkaloid that inhibits
mitosis.
Cold
Middle English
caeld cold
In weather, having a low atmospheric tempera-
ture. In life science, a common name for infec-
tions of the upper respiratory system.
Coleoptera
Greek
koleos- sheath
-pteron wing
Insect order having an anterior pair of hard and
horny wings covering a softer pair of posterior
wings, and two pairs of jaws adapted for feeding;
beetles, weevils.
Coleoptile
Greek
koleos- sheath
-ptilon plume
A protective sheath enclosing the shoot tip and
embryonic leaves of grasses.
Collagen
Greek
kolla- glue
A tough, fibrous protein occurring in vertebrates
as the chief constituent of collagenous tissue, and
also occurring in invertebrates—for example, in
the cuticle of nematodes.
Collembola
Greek
kolla- glue
-mbolon wedge, peg
Springtail; minute insect that lacks wings and has
a ventral tube, or collophore, on the first abdomi-
nal segment and an abdominal forked furcula, or
spring used to propel the organism forward.
Collenchyma
Greek
col- with, together
-khumos juice
Tissues that provide mechanical support in many
young, growing plant structures (stems, petioles,
leaves) but are uncommon in roots.
Collencyte
Greek
kolla- glue
A type of cell in sponges that secretes fibrillar
collagen.
Colligative
Latin
com- together, with; joint; jointly
-lig re- to tie, bind
Depending on the quantity of molecules but not
on their chemical nature.
Colloblast
Greek
kolla- glue
Aglue-secretingcellonthetentaclesofctenophores.
Colloid
Greek
kolla- glue
A suspension of final divided particles in a con-
tinuous medium.
Collophore
Greek
kolla- glue
A suckerlike organ at the base of the abdomen of
insects belonging to Collembola (springtails).
Colon
Greek
kolon large intestine
The section of the large intestine extending from
the cecum to the rectum.
Combustion
Latin
com- (con) together, with, jointly
-bustus- to burn
A chemical process accompanied by the evolu-
tion of light and heat.
Comet
Greek
kometes long-haired
A celestial body in an elliptical orbit around the
sun; a brightly illuminated mass composed of ice
and rock and displaying a long, glowing tail when
its orbit takes it near the sun.
i
a
e

48 Commensalism
Commensalism
Latin
-mensa- table
A relationship between organisms where one ben-
efits while the other is unaffected; sharing a meal.
Commissure
Latin
-mittere to put
A point or line of union or junction, especially
between two anatomical parts, such as the tract of
nerve fibers passing from one side to the other of
the spine or brain.
Community
Latin
communis- commons
-ity state or quality of
All of the populations of all species existing
together within an ecological system.
Competition
Latin
-peter- to strive
The struggle for existence among organisms.
Complex
Latin
-plexus an embrace
A group of items, such as chemical molecules,
that are related in structure or function.
Component
Latin
-ponere- to put together
-entcausinganaction;beinginaspecificstate;within
Unit resulting from the subdivision of a vector
into axial parts.
Compound
Latin
-ponere to put
A pure substance that is composed of two or more
elements in fixed proportions and that can be
chemically decomposed into these elements.
Compression
Latin
-premere- to press
An increase in the density of something as a result
of compacting.
Concave
Latin
-cavare to make hollow
Curved like the interior of an arched circle.
Concentric
Latin
-centrum center
Describing circles within circles, with the system
having a common center.
Conchoidal
Greek
conch- shell
-id- state, condition; having, being, pertaining to
or character of
Of, relating to, or being a surface characterized by
smooth, shell-like convexities and concavities, as
on fractured obsidian.
Concurrent
Latin
-currere to coincide
Happening at the same time or operating in con-
junction with one another.
Condensation
Latin
-dens- to press close together
The process by which a gas changes to a liquid.
Conduction
Latin
-ducere- to bring together
The flow of electron through a material to pro-
duce electric current.
Conductive
Latin
Exhibiting the power or ability to conduct or
transmit heat, electricity, or sound.

Constipation 49
Conductor
Latin
-or person or thing that does something
A substance or medium that conducts heat, light,
sound, or especially an electrical charge.
Congenital
Latin
-genitus- born; to bear
or character of
Of or relating to a condition that is present at birth.
Conidiophore
Greek
konis- dust
A specialized fungal form that asexually pro-
duces conidial spores.
Conidium
Greek
konis dust
An asexually produced fungal spore, formed on a
conidiophore.
Conifer
Greek
konos- cone
-ferre to bear
Any of an order of mostly evergreen trees and
shrubs with true cones and others (such as yews)
with an arillate fruit.
Coniferous
Latin
konos- cone
-ferre- to bear
Relating to the groups of plants that bear cones
(pines and cypress).
Coniine
Greek
koneion- poison hemlock
-ine a chemical substance; of or relating to
A poisonous, colorless liquid alkaloid found in
poison hemlock.
Conjugation
Latin
com- (con) together, with, jointly; compress,
converge
-jugare- to join together
The joining of unicellular organisms to exchange
hereditary material.
Conjunctiva
Latin
converge
-jungere- to join
-iva of the quality of; tending to, inclined to
The mucous membrane that lines the inner surface
of the eyelid and the exposed surface of the eyeball.
Conodont
Greek
konos- cone
-odontos tooth
Toothlike element from a Paleozoic animal now
believed to have been an early marine vertebrate.
Conscious
converge
-scire- to know
Being aware and having perception of one’s own
existence, sensations, and thoughts and of the sur-
rounding environment.
Conservation
Latin
converge
-servare- to preserve
The process of protecting, preserving, and using
wisely the natural resources.
Constant
Latin
converge
-stare to stand firm
A numerical value that does not change.
Constellation
Latin
converge
-stella- star
A group of stars that form a pattern.
Constipation
Latin
converge
-stipare- to press together
Infrequent and difficult movement of bowels.

50 Constrictor
Constrictor
Latin
converge
-stingere- to pull
-or condition or property of things or persons;
A muscle that contracts a cavity or orifice or com-
presses an organ.
Consumer
Latin
converge
-sumere- to take
Any organism that is incapable of producing its
own food by photosynthesis or chemosynthesis;
it derives its nutrients through the consumption of
producers or other consumers.
Contagious
Latin
converge
-teg- touch, reach, handle
Transmissible by direct or indirect contact; capa-
ble of transmitting disease; spreading or tending
to spread from one to another; infectious.
Continent
Latin
converge
-tenere- to hold together
-entcausinganaction;beinginaspecificstate;within
One of the principal land masses of the earth.
Contour
Latin
converge
-torn re to round off
Feathers that make up general outline of a bird.
Contusion
Latin
converge
-tundere- to beat
An injury in which the skin is not broken, often
characterized by ruptured blood vessels and dis-
coloration; a bruise.
Convection
Latin
converge
-vehere- to carry
Transferofenergybytheflowofaheatedsubstance.
Conversion
Latin
converge
-vertere- to turn around
The process in which something is changed from
one use, function, or purpose to another.
Convex
Latin
converge
-vextus to be vaulted
Having a surface that curves outward.
Copepod
Greek
kope- oar
-pod foot
Any of numerous minute marine and freshwater
crustaceans of the subclass Copepoda, having an
elongated body and a forked tail.
Coprophagy
Greek
kopros- dung
-phagei- to eat
Feeding on dung or excrement as a normal behav-
ior among animals; reingestion of feces.
Cornea
Latin
corneus horny
The outer transparent, convex part of the front of the
eyeball; it covers the iris and the pupil of the eye.
Corniculate
Latin
corniculum horn, hornlike structure
Bearing or furnished with one or more small horns.
Corolla
Latin
corolla small garland
Whorl of a flower that consists of the petals.
Corona
Latin
corona crown
The luminous, irregular envelope of highly ionized
gas outside the chromosphere of the sun.
a

Couple 51
Coronary
Latin
corona- crown
Of, relating to, or being the coronary arteries or
coronary veins; of or relating to the heart.
Corrugator (supercilii)
Latin
converge
-rigare- to wrinkle
A muscle of the eyelid, located under the eye-
brow, functioning to draw the eyebrow downward
and inward, wrinkling the adjacent skin.
Cortex
Latin
cortic bark, rind, that which is stripped off
The outer layer of an internal organ or body struc-
ture, as of the kidney or adrenal gland; the outer
layer of gray matter that covers the surface of the
cerebral hemisphere.
Cosmic
Greek
kosmos universe
Of or relating to the universe, especially as dis-
tinct from earth.
Cosmochemistry
Greek
kosmos- universe, order
-khemeia- chemical; alchemy
-y place for an activity, condition, or state
The science of the chemical composition of the
universe.
Cosmogony
Greek
-gonos offspring
The astrophysical study of the origin and evolu-
tion of the universe.
Cosmology
Greek
bodies of knowledge
The study of the physical universe considered as a
totality of phenomena in time and space.
Costalgia
Latin
costo- rib
Plueritic pain in the chest.
Costocervical
Latin
costo- rib
-cervic- stem of cervix
or character of
Concerning the ribs and the neck.
Costoinferior
Latin
costo- rib
-inferus below, low
Relating to the lower rib.
Costophrenic
Latin
costo- rib
-phren- diaphragm, midriff, heart
Referring to the ribs and diaphragm.
Costopneumopexy
Latin
costo- rib
-pneumon- wind, breath
-pexy attaching; surgical fixation of an organ
The surgical anchoring of a lung to a rib.
Costosuperior
Latin
costo- rib
-superus higher, upper
Relating to the upper rib.
Costotome
Latin
costo- rib
An instrument designed to cut through ribs.
Cotyledon
Greek
kotuledon a kind of plant; a seed leaf; a hollow or
cup-shaped object
The one or two seed leaves of an angiosperm
embryo.
Coumarin
Portuguese
cumaru- tonka bean tree
-in neutral chemical; protein derivative
A fragrant crystalline compound extracted from
several plants and widely used in perfumes.
Couple
Latin
copula bond or pair
A pair of forces of equal magnitude acting in par-
allel but opposite directions.

52 Covalence
Covalence
Latin
co- to the same extent or degree; together, jointly
-valere to be strong
The number of electron pairs an atom can share
with other atoms.
Covariant
Latin
co- to the same extent or degree; together, jointly
-variare to vary
Expressing or relating to the principle that physi-
cal laws have the same form regardless of the
coordinate system in which they are expressed.
Coxopodite
Latin
coxa- hip
-podos- foot
-ite component of a part of the body
The proximal joint of an insect or arachnid leg; in
crustaceans, the proximal joint of the protopod.
Cracking
Middle English
cracian- to break apart
-ing the act of
Thermal decomposition of a complex substance.
Craniomalacia
Greek
kranion- skull
Softening of the bones of the skull.
Cranium
Greek
kranion skull
The part of the skull that encloses the brain.
Crater
Greek
krater bowl for mixing wine and water
Funnel-shaped pit or depression at the top of a
volcanic cone.
Creatinine
Greek
kreat- flesh
A waste product of protein usage in cells; nitrog-
enous wastes excreted in urine.
Cremaster
Latin
crem- to hang; hung, hung up
-ster one that is associated with, participates in,
makes, or does
The hooklike process on the end of a chrysalis that
attaches the pupa to the stem or twig, for example.
Crepuscular
Latin
creper- dark
In biology, relating to organisms that become
active after twilight (e.g., bats).
Cretaceous
Latin
creta- chalk
-eousfullof,havingthequalityornatureof,relatingto
The final period of the Mesozoic era, spanning
the time between 145 and 65 million years ago.
Crevasse
French
crevace crevice
A deep fissure; a chasm.
Crocodile
Greek
kroke- pebble
-drilos circumcised man; worm
The name given to various large aquatic reptiles
found in the tropics and subtropics with thick,
bumpy skin and long, tapered jaws.
Crop
Old English
cropp craw
A pouched enlargement of the gullet that serves
as a receptacle for food and for its preliminary
maceration.
Crust
Latin
crusta shell, hard surface of a body
The outermost layer of the earth’s surface, extend-
ing downward about 20 miles on the land masses
and 3 to 10 miles down beneath the ocean floor.
Crustacean
Latin
crusta- shell, hard surface of a body
-acean belonging to a taxonomical group
One of the classes of the phylum Arthropoda pos-
sessing shells.
Cryptobiotic
Greek
kryptos- hidden
Living in concealment; refers to insects and other
animals that live in secluded situations, such as
underground or in wood, and also to tardigrades
and some nematodes, rotifers, and others that sur-
vive harsh environmental conditions by assuming
for a time a state of very low metabolism.

Cycloalkane 53
Crystal
Latin
krustallos- ice, crystal; freeze; icelike
or character of
Very clear glass; a homogeneous solid formed by
a repeating three-dimensional pattern.
Crystalline
Greek
Resembling crystal, as in transparency or dis-
tinctness of structure or outline.
Crystallization
Greek
Theprocessofformingsolidcrystalsinsolutiondue
to the solute solubility exceeding that of the solvent.
Culture
Latin
cult- to care for; to dwell, to inhabit
-ura act, process, condition
The growing of microorganisms, tissue cells, or
other living matter in a specially prepared nutrient
medium.
Cumulonimbus
Latin
cumul- pile or heap
-nimbus cloud
An extremely dense, vertically developed cumu-
lus with a glaciated top extending to great heights.
Cumulus
Latin
cumul- pile or heap
-us thing
Heap, Pile, or mass.
Cuspid
Latin
cuspis- sharp point, cusp
to, tending to, inclined to
Pointed or conical teeth, usually referring to the
canine teeth.
Cuticle
Latin
cutis skin
A waxy layer that coats the surface of stems,
leaves, and other plant parts exposed to air.
Cutoff
Old English
cutten- to separate into parts with or as if with a
sharp-edged instrument
-of no longer taking place; canceled
A new channel cut by a river across the neck of an
oxbow.
Cyanobacteria
Greek
cyano- (kyanos) blue, dark blue
-baktron- staff, rod
plurals
Microscopic, photosynthetic prokaryotes that
formed stromatilites and changed the earth’s
atmosphere by producing oxygen.
Cyanoderma
Greek
-derma skin
Bluish discoloration of the skin.
Cyanosis
New Latin
Bluish discoloration of the skin due to deficient
oxygenation of the blood.
Cycads
Greek
cyc- (koïx) a kind of palm tree, perhaps of Egyptian
origin
-ad member of a botanical group
Any of an order (Cycadales) of dioecious cycado-
phytes that are represented by a single surviving
family (Cycadaceae) of palmlike tropical plants
that reproduce by means of spermatozoids.
Cyclase
Greek
kyklos- circle, wheel, cycle; rotate
-ase indicating an enzyme
Enzyme that forms a cyclic compound.
Cycle
Greek
kyklos circle, wheel, cycle, rotate
An interval of time during which a sequence of a
recurring events or phenomena is completed.
Cycloalkane
Greek
-alkyl- alcohol; a monovalent radical, such as
ethyl or propyl
-ane a saturated hydrocarbon
An alicyclic hydrocarbon with a saturated ring;
also called cycloparaffin.

54 Cyclonic
Cyclonic
Greek
An atmospheric system characterized by the rapid
inward circulation of air masses about a low-
pressure center, usually accompanied by stormy,
often destructive weather. Cyclones circulate
counterclockwise in the Northern Hemisphere
and clockwise in the Southern Hemisphere.
Cyclotron
Greek
-tron device for manipulating subatomic particles
A circular particle accelerator in which charged
subatomic particles are accelerated outward in a
plane perpendicular to a fixed magnetic field by
an alternating electric field.
Cygnus
Latin
cygnus swan
A constellation in the Northern Hemisphere near
Lacerta and Lyra, containing the star Deneb; also
called the Northern Cross or the Swan.
Cystic
Greek
kustis- (cyst) sac or bladder that contains fluid
Of or related to a fluid-filled sac; a cyst or cystlike
object. In anatomy, relating to the gallbladder or
urinary bladder.
Cysticercus
Greek
-kerkos tail
A type of juvenile tapeworm in which an invagi-
nated and introverted scolex is contained in a
fluid-filled bladder.
Cystidolaparotomy
Greek
-lapar- soft part of the body between the ribs, hip,
and flank; the loin
Incision of the bladder through the abdominal wall.
Cystitis
Latin
-itis inflammation
Inflammation of the urinary bladder.
Cystocele
Greek
-kele hernia, tumor
A herniation of the urinary bladder through the
wall of the vagina.
Cystoscopy
Greek
The process of examining the urinary bladder by
looking into it with a scope instrument.
Cytoglucopenia
Greek
kutos- (cyto) sac or bladder that contains fluid
-gluc- glucose
-penia reduction, poverty, lack, deficiency
An intercellular deficiency of glucose.
Cytokine
Greek
-kinein to move
Any of several regulatory proteins, such as the
interleukins and lymphokines, that are released by
cells of the immune system and act as intercellular
mediators in the generation of an immune response.
Cytokinesis
Greek
-kine- movement, motion
The division of the cytoplasm of a cell following
the division of the nucleus.
Cytokinin
Greek
-k nein to move
Any of a class of plant hormones that promote
cell division and growth and delay the senescence
of leaves.
Cytolysis
Greek
The dissolution or destruction of a cell.
Cytopharynx
Greek
-pharynx throat
Short tubular gullet in ciliate protozoa.
i

Cytotoxicity 55
Cytoplasm
Greek
-plasm (plassein) to mold or form cells or tissues
Substance of the body of a cell excluding the
nucleus.
Cytoproct
Greek
-proktos anus
Site on a protozoan where indigestible matter is
expelled.
Cytopyge
Greek
-pyge rump, buttocks
In some protozoa, localized site for expulsion of
waste.
Cytoskeleton
Greek
-skeletos dried body
A network of interconnected filaments and
tubules that extends from the nucleus to the
plasma membrane in eukaryotic cells.
Cytosol
Greek/Latin
-solvere to loosen
The fluid component of cytoplasm, excluding
organelles and the insoluble, usually suspended
cytoplasmic components.
Cytostome
Greek
-stoma mouth
Themouthofaunicellularorganism,sometimescon-
sisting of a hollow tube and a groovelike opening.
Cytotoxicity
Greek
-toxikos- poison
-ity state or quality of
The state or quality of being toxic to cells.

Dactylozooid
Greek
dactylo- finger, toe
-zoon- animal, animal-like
A hydroid modified for catching prey; it is long,
with tentacles or short knobs, and with or without
a mouth.
Data
Latin
datum something given
Factualinformation,especiallyinformationorganized
for analysis or used to reason or make decisions.
Decantation
Latin
de- do or make the opposite of, reverse the action
of, undo; from, apart, away
-canthus- rim of a wheel or vessel
The process of separating a mixture of two or more
layers by pouring layers into separate containers.
Decapoda
Greek
deca- ten
-pod foot
The order of crustaceans, which includes the
shrimps, lobsters, crabs, etc.
Decay
Latin
-cadere to fall
To break down into component parts.
Deciduous
Latin
decidu- to fall off
Falling off at a specific season or stage of growth.
Decipher
Latin/Arabic
-safira- to be empty
To read, interpret, or convert complex, sometimes
ambiguous data into a simplified form.
Declination
Greek
-klinein- to lean; sloping
-ation action, process, state, or condition
A measure of how far north or south an object is
from the celestial equator.
Decomposer
Latin
-compose- to form, create
Organismthatfeedsonandbreaksdowndeadmatter.
Defect
Latin
-fecere make, do, cause, produce, build
e

Dental 57
An imperfection that causes inadequacy or fail-
ure; a shortcoming.
Deglutination
Latin
-glutinare- to glue
The act of ungluing; the process of removing the
gluten from flour.
Deglutition
Latin
-gl t re- to gulp
The act or process of swallowing.
Degradation
Latin
-gradus- walk, step, take steps, move around;
walking or stepping
To reduce the complexity of. In geology, the pro-
cess of wearing away at the earth’s surface through
erosion.
Dehiscent
Latin
-hiare- to gape
-ent causing an action, being in a specific state;
within
The opening of a fruit to liberate the seeds.
Deletion
Latin
deletus- to erase, destroy
The loss of a piece of chromosome that has bro-
ken away from the genetic material.
Deliquescent
Latin
deliquiscere melt by absorption of moisture
-entcausinganaction,beinginaspecificstate;within
Asubstancethatabsorbsenoughwaterfromtheair
that it dissolves completely to a liquid solution.
Dendrite
Greek
dendro- tree, resembling a tree
-ite a part of or product of
A branching, treelike extension from the body of
a nerve cell that detects nerve impulses transmit-
ted from the axons of other neurons.
Dendrochore
Greek
-chore a central and often foundational part, usu-
ally distinct from the enveloping part by a differ-
ence in nature
That part of the earth’s surface covered by trees.
Dendrochronology
Greek
-khronos- time
bodies of knowledge
A method of dating using annual tree rings; tree
ring chronology.
Dendroclastic
Greek
Breaking or destroying trees; a destroyer of trees.
Dendroclimatology
Greek
-klinein- to lean; sloping
-ate- characterized by having
bodies of knowledge
The determination of past climatic conditions
from the study of the annual growth rings of trees.
Dendrohydrology
Greek
-hydr- water
bodies of knowledge
The study of tree ring configuration to determine
hydrologic occurrences.
Density
Latin
densi- thick, thickly set, crowded, compact
The state or quality of being dense; compactness;
closely set or crowded condition. Density is a
measure of mass per unit of volume.
Dental
Latin
denti- teeth or tooth
or character of
Of or relating to the teeth or to dentistry.
u i

58 Dentalgia
Dentalgia
Greek/Latin
An aching pain in or near a tooth; toothache.
Dentifrice
Latin
-frice to rub; a rubbing
A powder or other preparation for cleansing or
rubbing the teeth; a tooth powder or paste.
Dentition
Latin
The number, type, and arrangement of an ani-
mal’s teeth.
Deposit
Latin
-ponere to put
To lay down or leave behind by a natural process;
to settle down in layers, as in mineral deposits.
Depressor
Latin
-premere- to press
A muscle that draws down a part of the body; a
substance that slows a physiological activity.
Dermal
Greek
derm- skin
or character of
Of or relating to the skin or dermis.
Dermatologist
Greek
dermat- skin
-logist one who deals with a specific topic
A physician who specializes in the diagnosis and
treatment of skin disorders.
Dermatophyte
Greek
dermat- skin
-phyte plant
Any one of a number of fungi that infect the skin
and nails.
Dermatozoon
Greek
dermat- skin
-zoon animal
Reference to animal skin or a branch of medicine
dealing with animals.
Desiccator
Latin
desiccare make quite dry
A device used for drying substances; a closed
glass vessel containing a deliquescent substance.
Desmoplastic
Greek
desmo- bond, adhesion
Pertaining to the production or formation of
adhesions or fibrosis in the vascular connective
tissue framework of an organ.
Detergent
Latin
de- out, off, apart, away
-terr re- to frighten
-agere to do
A cleansing substance that acts similarly to soap
but is made from chemical compounds rather
than fats and lye.
Detritivore
Latin
deterere- to wear away, rub, grind; worn down
-vore eat, consume, ingest, devour
An organism that lives on dead and discarded
organic matter; includes large scavengers, smaller
animals such as earthworms and some insects, as
well as decomposers (fungi and bacteria).
Detritus
Latin
deterere to lessen, wear away
Loose material (stone fragments, silt, etc.) that is
worn away from rocks.
Deuterium
Greek
deuteros- second, two in number
-ium chemical element
An isotope of hydrogen with one proton and one
neutron in the nucleus.
Deuterostome
Greek
deuteros- second, two in number
-stoma mouth
An animal whose mouth forms from an opening
other than the blastopore.
e

Dichroism 59
Dextrorotatory
Latin
dextra- right or clockwise
-rota- wheel
-ory of or pertaining to
Rotating to the right in a plane of polarized light.
Diagnose
Greek
dia- through, across, apart
-gnose to know or learn
To arrive at a conclusion or determine the cause of a
disorder or disease, usually by deductive reasoning.
Diagnosis
Greek
-gno- to come to know
The act or process of identifying or determining
the nature and cause of a disease.
Diaheliotropism
Greek
-helio- sun
stimulus
A tendency of leaves to have their dorsal surface
toward the rays of the sun.
Dialysis
Greek
The separation of smaller molecules from larger
molecules or of dissolved substances from colloi-
dal particles in a solution by selective diffusion
through a semipermeable membrane.
Diamagnetic
Greek
-magn s-stone from Magnesia (city in Asia Minor)
A substance that is weakly repelled by a magnet.
Diaphragm
Greek
-phragma fence
Muscular partition between the chest and abdom-
inal cavities.
Diapsids
Greek
di- two
-apsis arch
Amniotes in which the skull bears two pairs of
temporal openings; includes reptiles (except tur-
tles) and birds.
Diarrhea
Greek
-rhein to flow or run
Frequent and possibly excessive elimination of
watery feces.
Diastereomer
Greek
di- two
-a- without, not
stereos- being of three dimensions
-mer one that has
Two compounds that are optical isomers that are
not mirror images of each other, with different
physical properties and reactivity.
Diastole
Greek
diast- dilation, spreading
-ole little
Relaxation period of a heart during the cardiac cycle.
Diatom
Greek
Any of a class of minute planktonic unicellular or
colonial algae with silicified skeletons that form
diatomite.
Diatomic
Latin
di- two, twice, double
-a- no, absence of, without, lack of, not
-tomos- (temnein) to cut, incise, section
Consisting of or relating to a molecule that is
composed of two atoms.
Dichotomy
Greek
dicho- akin to
A dividing or branching into two equal parts.
Dichroism
Greek
-khr ma- color
The property of showing two different colors at
different concentrations or when viewed at differ-
ent angles.
e
o

60 Dicotyledon
Dicotyledon
Greek
-kotuledon a kind of plant; a seed leaf; a hollow
or cup-shaped object
Flowering plant group whose members have two
embryonic leaves.
Dictyostele
Greek
dictyo- net, netlike
-stele pillar
In some ferns, a stele that is interrupted by leaf
gaps so as to resemble a network of strands.
Diencephalon
Greek
dia- through
-enkephalos in the head
The posterior portion of the forebrain; includes
areas of the midbrain such as the thalamus and
hypothalamus.
Differentiation
Latin
differre- to differ; delay
-atus- in
The process by which cells or tissues undergo a
change toward a more specialized form or func-
tion, especially during embryonic development.
Diffraction
Latin
dis- undo; apart, in all directions
-frangere- to break
Change in the directions and intensities of a
group of waves after passing by an obstacle or
through an aperture whose size is approximately
the same as the wavelength of the waves.
Diffusion
Latin
diffundere- to spread out
The process in which particles in a fluid move
from an area of higher concentration to an area of
lower concentration.
Digest
Latin
digerere to break down
To break into smaller parts and simpler compounds.
Digestion
Latin
di- apart, away, from
-gerere- to bear
The ability to change into absorbable form.
Digitigrade
Latin
digitus- finger or toe
-gradus step or degree
Walking on the digits with the posterior part of
the foot raised.
Dihybrid
Greek
-hybrida- mongrel offspring
The offspring of parents differing in two specific
gene pairs.
Dilation
Latin
-l tus wide
The process of becoming wider or larger, as of a
blood vessel.
Dilute
Latin
-luere wash, clean
To make thinner or less concentrated by adding a
liquid such as water.
Dimension
Latin
dis- undo; apart, in all directions
-metiri- to measure out
Ameasurementofspatialextent;specifically,oneof
three coordinates determining a position in space.
Dimorphism
Greek
The existence within a species of two distinct
forms according to color, sex, organ structure, or
other characteristic.
Dinoflagellate
Greek
dinos- whirling
-flagrum- whip
A marine protozoan of the order Dinoflagellata,
having two flagella and a cellulose covering and
forming one of the chief constituents of plankton.
a

Displacement 61
They include bioluminescent forms and forms
that produce red tide.
Dinosaur
Greek
deinos- terrible, monstrous
-sauros lizard
A variety of extinct reptiles that existed during
the Mesozoic era.
Dioecious
Greek
-oec- environment, habitat
-ious full of, having the quality of, relating to
Having the male and female reproductive organs
in separate individuals.
Diphycercal
Greek
diphues- twofold
-kerkos- tail
or character of
Having a tail that tapers to a point, as in lung-
fishes; the vertebral column extends to tip with-
out upturning.
Diphyodont
Greek
-phuein- to grow
-odont having teeth
Having deciduous and permanent sets of teeth
successively.
Diploblastic
Greek
diploos- double
Referring to an organism with two germ layers,
endoderm and ectoderm.
Diploid
Greek
diploos- double
Having the somatic (double, or 2n) number of
chromosomes, or twice the number characteristic
of a gamete of a given species.
Diplopia
New Latin
diploos- double
-optic- eye, optic
Latinizing plurals
Condition in which two images of a single object
are seen due to unequal action of the eye muscles;
also called double vision.
Dipole
Middle English from Old French (from Latin)
-pole either of two oppositely charged terminals
A pair of equal and opposite electrical charges or
magnetic poles, separated by a small distance.
Disaccharide
Greek
-saccharon- sugar
Any class of sugars, including lactose and
sucrose, that are composed of two monosaccha-
rides; a double sugar.
Disease
Middle French
dis- apart, away from; utterly, completely, in all
directions
-aise ease, freedom from pain
A condition of the living animal or plant body or
of one of its parts that impairs normal functioning.
Dispersion
Latin
directions
-spargere- to scatter or strew; sprinkle
The passing out or spreading about of something.
Dispersoid
Latin
directions
-spargere- to scatter or strew; sprinkle
-oid (oeid s) resembling, having the appearance
of
A substance consisting of finely divided particles
dispersed in a medium.
Displacement
Greek
dis- apart, away fro;, utterly, completely, in all
directions
-place- to put in or as if in a particular place or
position
fied) action
A vector or the magnitude of a vector from an ini-
tial position to a subsequent position assumed by
a body.
e
e

62 Dissection
(Continued)
Dissection
Latin
directions
-sectus- to cut
The separation of a whole into its parts for study.
Disseminate
Latin
directions
-seminare- to plant or propagate (from semen,
seminis, meaning “seed”)
To scatter for growth and propagation; to spread,
to diffuse.
The Black Death
The black plague struck continental Europe in the
year 1347. Without a doubt, it was one of the most
devastating natural disasters ever to befall human-
kind. In many ways it altered the course of human
history. The epidemiology of plague was a mystery
to all. Even while it was happening, no one really
knew its cause, let alone its cure. Thousands of peo-
ple died, and others fled. Those who treated the
very ill died. Those who buried the dead died.
Today, historians and scientists believe that the
Black Death stemmed from a microorganism called
Yersinia pestis, a bacterium that was carried and
spread by fleas living on black rats. During that era,
the black rat population vastly exceeded that of the
larger and fiercer Norwegian gray rat. Interestingly,
the Norwegian gray rat was a poor vector for the
fleas carrying the bacteria.
In the late 1370s and early 1380s, Marchione di
Coppo Stefani wrote the descriptive narrative The
Florentine Chronicle on Medieval Plague. Excerpts
from that essay describe the horror of the plague:
In the year of the Lord 1348 there was a very
great pestilence in the city and district of Flo-
rence. It was of such a fury and so tempestuous
that in houses in which it took hold previously
healthy servants who took care of the ill died of
the same illness. Almost none of the ill sur-
vived past the fourth day. Neither physicians
nor medicines were effective. Whether because
these illnesses were previously unknown or
because physicians had not previously studied
them, there seemed to be no cure. There was
such a fear that no one seemed to know what to
do. When it took hold in a house it often hap-
pened that no one remained who had not died.
And it was not just that men and women died,
but even sentient animals died. Dogs, cats,
chickens, oxen, donkeys, sheep showed the
same symptoms and died of the same disease.
And almost none, or very few, who showed
these symptoms, were cured. The symptoms
were the following: a bubo in the groin, where
the thigh meets the trunk; or a small swelling
under the armpit; sudden fever; spitting blood
and saliva (and no one who spit blood survived
it). It was such a frightful thing that when it got
into a house, as was said, no one remained.
Frightened people abandoned the house and
fled to another. Those in town fled to villages.
Physicians could not be found because they had
died like the others. And those who could be
found wanted vast sums in hand before they
entered the house. And when they did enter,
they checked the pulse with face turned away.
They inspected the urine from a distance and
with something odoriferous under their nose.
Child abandoned the father, husband the wife,
wife the husband, one brother the other, one
sister the other. In all the city there was nothing
to do but to carry the dead to a burial. And those
who died had neither confessor nor other sacra-
ments. And many died with no one looking
after them. And many died of hunger because
when someone took to bed sick, another in the
house, terrified, said to him:
“I’m going for the doctor.” Calmly walking
out the door, the other left and did not return
again. Abandoned by people, without food, but
accompanied by fever, they weakened. There
were many who pleaded with their relatives not
to abandon them when night fell. But [the rela-
tives] said to the sick person, “So that during
the night you did not have to awaken those who
serve you and who work hard day and night,
take some sweetmeats, wine or water. They are
here on the bedstead by your head; here are
some blankets.” And when the sick person had
fallen asleep, they left and did not return. If it
happened that he was strengthened by the food
during the night he might be alive and strong
enough to get to the window. If the street was
not a major one, he might stand there a half
hour before anyone came by. And if someone
did pass by, and if he was strong enough that he
could be heard when he called out to them,
sometimes there might be a response and
sometimes not, but there was no help. No one,
or few, wished to enter a house where anyone

Disseminate 63
(Continued)
was sick, nor did they even want to deal with
those healthy people who came out of a sick
person’s house. And they said to them: “He is
stupefied, do not speak to him!” saying fur-
ther: “He has it because there is a bubo in his
house.” They call the swelling a bubo. Many
died unseen. So they remained in their beds
until they stank. And the neighbors, if there
were any, having smelled the stench, placed
them in a shroud and sent them for burial. The
house remained open and yet there was no one
daring enough to touch anything because it
seemed that things remained poisoned and that
whoever used them picked up the illness. At
every church, or at most of them, they dug
deep trenches, down to the waterline, wide
and deep, depending on how large the parish
was. And those who were responsible for the
dead carried them on their backs in the night
in which they died and threw them into the
ditch, or else they paid a high price to those
who would do it for them. The next morning,
if there were many [bodies] in the trench, they
covered them over with dirt. And then more
bodies were put on top of them, with a little
more dirt over those; they put layer on layer
just like one puts layers of cheese in a lasagna.
The beccamorti [literally, vultures] who
provided their service, were paid such a high
price that many were enriched by it. Many
died from [carrying away the dead], some
rich, some after earning just a little, but high
prices continued. Servants, or those who took
care of the ill, charged from one to three flor-
ins per day and the cost of things grew. The
things that the sick ate, sweetmeats and sugar,
seemed priceless. Sugar cost from three to
eight florins per pound. And other confections
cost similarly. Capons and other poultry were
very expensive and eggs cost between twelve
and twenty-four pence each; and he was
blessed who could find three per day even if
he searched the entire city. Finding wax was
miraculous. A pound of wax would have gone
up more than a florin if there had not been a
stop put [by the communal government] to the
vain ostentation that the Florentines always
make [over funerals]. Thus it was ordered that
no more than two large candles could be car-
ried [in any funeral]. Churches had no more
than a single bier which usually was not suffi-
cient. Spice dealers and beccamorti sold biers,
burial palls, and cushions at very high prices.
Dressing in expensive woolen cloth as is cus-
tomary in [mourning] the dead, that is in a
long cloak, with mantle and veil that used to
cost women three florins climbed in price to
thirty florins and would have climbed to 100
florins had the custom of dressing in expensive
cloth not been changed. The rich dressed in
modest woolens, those not rich sewed
[clothes] in linen. Benches on which the dead
were placed cost like the heavens and still the
benches were only a hundredth of those
needed. Priests were not able to ring bells as
they would have liked. Concerning that [the
government] issued ordinances discouraging
the sounding of bells, sale of burial benches,
and limiting expenses. They could not sound
bells, sell benches, nor cry out announcements
because the sick hated to hear of this and it dis-
couraged the healthy as well. Priests and friars
went [to serve] the rich in great multitudes and
they were paid such high prices that they all
got rich. And therefore [the authorities]
ordered that one could not have more than a
prescribed number [of clerics] of the local par-
ish church. And the prescribed number of fri-
ars was six. All fruits with a nut at the center,
like unripe plums and unhusked almonds,
fresh broadbeans, figs and every useless and
unhealthy fruit, were forbidden entrance into
the city. Many processions, including those
with relics and the painted tablet of Santa
Maria Inpruneta, went through the city crying
our “Mercy” and praying and then they came
to a stop in the piazza of the Priors. There they
made peace concerning important controver-
sies, injuries and deaths. This [pestilence] was
a matter of such great discouragement and fear
that men gathered together in order to take
some comfort in dining together. And each
evening one of them provided dinner to ten
companions and the next evening they planned
to eat with one of the others. And sometimes if
they planned to eat with a certain one he had no
meal prepared because he was sick. Or if the
host had made dinner for the ten, two or three
were missing. Some fled to villas, others to
villages in order to get a change of air. Where
there had been no [pestilence], there they car-
ried it; if it was already there, they caused it to
increase. None of the guilds in Florence was
working. All the shops were shut, taverns
closed; only the apothecaries and the churches
remained open. If you went outside, you found
almost no one. And many good and rich men
were carried from home to church on a pall by
four beccamorti and one tonsured clerk who
carried the cross. Each of them wanted a florin.

64 Dissociation
Dissociation
Latin
directions
-sociar- to join
The process by which a chemical combination
breaks up into simpler constituents.
Distillation
Latin
directions
-stillare- to drip or trickle
A process used to separate a liquid mixture based
on the boiling points of the substances within the
solution.
Distribution
Latin
directions
-tribuere- to give
In mathematics, sample values presented in order
from the lowest to the highest.
Diurnal
Latin
diurnus- day
or character of
Related to or occurring within a twenty-four-hour
period; occurring in the daytime hours rather than
the nighttime hours.
Diverge
Latin
-verge to tend to move in a particular direction
To go or extend in different directions from a
common point.
Diverticulum
Latin
de- reverse the action of, undo; from, apart, away
-vertere- to turn
A pouchlike structure extending out or away from
an organ such as the intestines.
DNA ligase
Latin
ligo- bind, tie
-ase enzyme
Enzyme that links DNA fragments; used during
the production of recombinant DNA to join for-
eign DNA to the vector DNA.
Dodecahedron
Greek
dodeca- twelve
-hedron face
A Platonic solid with twelve faces; the fifth
essence.
Doldrums
Middle English
dold to dull
A region of the ocean near the equator, character-
ized by calms, light winds, and squalls.
Domain
Latin
dominus lord
Any of numerous contiguous regions in a ferro-
magnetic material in which the direction of spon-
taneous magnetization is uniform and different
from that in neighboring regions.
This mortality enriched apothecaries, doc-
tors, poultry vendors, beccamorti, and
greengrocers who sold of poultices of mal-
low, nettles, mercury and other herbs neces-
sary to draw off the infirmity. And it was
those who made these poultices who made a
lot of money. Woolworkers and vendors of
remnants of cloth who found themselves in
possession of cloths [after the death of the
entrepreneur for whom they were working]
sold it to whoever asked for it. When the
mortality ended, those who found them-
selves with cloth of any kind or with raw
materials for making cloth was enriched.
But many [who actually owned cloths being
processed by workers] found it to be moth-
eaten, ruined or lost by the weavers. Large
quantities of raw and processed wool were
lost throughout the city and countryside.
This pestilence began in March, as was
said, and ended in September 1348. And peo-
ple began to return to look after their houses
and possessions. And there were so many
houses full of goods without a master that it
was stupefying. Then those who would inherit
these goods began to appear. And such it was
that those who had nothing found themselves
rich with what did not seem to be theirs and
they were unseemly because of it. Women and
men began to dress ostentatiously.

Ductile 65
Dominant (traits)
Latin
dominan dominant
Thehereditarytraitsthatexhibitastrongerinfluence
on the phenotype than their more recessive alleles.
Doping
Dutch
doopen- to dip
-ing the act of or action
The act of introducing impurities into a crystal
structure in order to acquire useful properties.
Dormant
Latin
dormire- to sleep
-ant a person who, the thing which
Describes an inactive state of a seed.
Dorsal
Latin
dorsalis- back
or character of
Of, toward, on, in, or near the back or upper sur-
face of an organ, part, or organism.
Downburst
Swedish
dun- down
-bresta to break asunder
Violent downdrafts that are concentrated in a
local area.
Drag
Old Norse
draga to draw, drag
The retarding force exerted on a moving body by
a fluid medium such as air or water.
Drosophila
Greek
drosos– dew
-philos beloved
Any of various small fruit flies of the genus
Drosophila.
Drought
Anglo-Saxon
dygre dry
Dryness; lack of rain or water.
Drumlin
Scottish Gaelic
drum- ridge, back; long, narrow hill
An elongated hill or ridge of glacial drift; elon-
gated landform that results when a glacier moves
over an older moraine.
Ductile
Latin
ductus- to be hammered out into a tube or pipe;
leading or drawing
-ile changing; ability; suitable; tending to
Property of a metal that enables it to be easily
drawn into a wire.
Pythagoras of Samos
During the reign of the tyrant Polycrates
(535–515 BC), the Greek island of Samos
in the eastern Aegean Sea was home to
Pythagoras. He was one of the most influ-
ential mathematicians and philosophers
of his time. All those who truly appreciate
mathematics hold a special place in their
hearts for the Pythagoreans, who believed
that numbers constitute the true nature
and harmony of the world—indeed, the
universe. That is, the synchronization of
the universe relies on mathematical har-
mony. The Pythagoreans did not believe
in experimentation. They relied on the
faculties of thought, reason, and deduc-
tion. Pythagoras’ followers (who called
themselves the mathematikoi) reasoned
that the relationships among all things
were mathematical. Even the workings of
the mind (logic and reason) were, to the
Pythagoreans, the result of mathematical
expressions.
Pythagoras is given credit for develop-
ing a mathematical correlation between
whole numbers and musical scales. He
and his followers are recognized for
developing the Pythagorean theorem,
which is well known among all who study
geometry. Beauty was to be found in the
shapes of solids. The four regular solids,
the tetrahedron, hexahedron (cube), octa-
hedron, and icosahedron, represented the
four elements (earth, fire, air, and water),
the “roots” of the earth. There was a
mystical, almost fearful forbiddance
directed toward the fifth of the regular sol-
ids, the dodecahedron. The Pythagoreans
believed that the twelve pentagons that
form the sides of this solid were somehow
celestial and not of this earth. This fifth
element, which could only come from the
heavens, signified by the dodecahedron
gave rise to the term quintessence: the
purest, most highly concentrated essence,
the “fifth essence.

66 Dunite
Dunite
English
dun- referring to Mount Dun in New Zealand
A dense igneous rock that consists mainly of oli-
vine and is a source of magnesium.
Duodenostomy
Latin/Greek
duodecum- twelve
-stoma- opening
The surgical establishment of an opening into the
duodenum.
Duodenum
Latin
duodeni- twelve each
The beginning portion of the small intestine,
approximately 12 inches in length, starting at the
lower end of the stomach and extending to the
jejunum.
Duramen
Latin/Middle English
durare- to harden; hard growth
-enen to cause or become
The older, nonliving central wood of a tree or
woody plant, usually darker and harder than the
younger sapwood.
Dynamic
Greek
dunamikos- powerful
Marked by usually continuous and productive
activity or change; of or relating to energy or to
objects in motion.
Dysentery (amoebic)
Greek
dys- painful, difficult, disordered, impaired,
defective, ill
-enteron- intestines
Extreme diarrhea with blood in the feces, caused
by either the ingestion of certain bacteria (shi-
gella) or protozoa (Entamoeba hystolitica).
Dysfunction
Greek/Latin
defective, ill
-fungi- performance, execution
Abnormal, inadequate, or impaired function of an
organ or body part.
Dyslexia
Greek
defective, ill
-legein- word, speech
or character of
A disorder affecting the comprehension and use
of words.
Dyspepsia
Greek
defective, ill
-peps- digestion
plurals
Commonly referred to as indigestion, a painful
disorder of the stomach.
Dysphagia
Greek
defective, ill
-phage- to eat
Latinizing plurals
Difficulty in swallowing, but not to be con-
fused with painful swallowing. Dysphagia is a
symptom of numerous paralytic diseases, includ-
ing amyotrophic lateral sclerosis (Lou Gehrig’s
disease).
Dyspnea
Greek
defective, ill
-pnoia breathing or breath
Sensation of difficult or labored breathing.
Dystrophy
Greek
defective, ill
development
Any of several disorders involving atrophy of
muscular tissue.

Eccentric
Greek
ek- out of
-kentron- center
Deviating from a circular form or path, as an
elliptical orbit.
Eccentricity
Greek
ek- out of
-kentron- center
-itas variant
The measure of the degree of elongation of an
ellipse. For example, a circle has an eccentricity
of 0, and a parabola (an open figure) has an eccen-
tricity of 1.
Eccrine
Greek
ek- out of
Applies to a type of mammalian sweat gland that
produces a watery secretion.
Ecdysiotropin
Greek
ekdysis- to strip off; escape
stimulus
Hormone secreted in the brain of insects that
stimulates the prothoracic gland to secrete molt-
ing hormone.
Ecdysone
Greek
ekdusis- to shed or molt
-one a chemical compound containing oxygen in
a carbonyl group
A steroid hormone, produced by the prothoracic
gland of insects, that promotes growth and con-
trols molting.
Echinoderma
Greek
echino- spiny, hedgehog
-derma skin
Radially symmetrical marine invertebrates,
including starfish and sea urchins.
Echocardiograph
Greek
kh - repeat of sound
A technological instrument designed to noninva-
sively transmit ultrasonic impulses into the chest
that are reflected back so that the heart can be
imaged and studied.
Echolocation
Greek
kh - repeat of sound
-locare to place
A sensory adaptation used by certain animals
such as dolphins and bats. Pulses of sound waves
are emitted by the animal and reflected back from
an object; the organism can then determine the
distance of the object by the elapsed time.
e o
e o

68 Eclipse
Eclipse
Greek
ektos- outer, external, out of, out, outside; away from
-leipein to leave
The partial or complete obscuring, relative to a des-
ignated observer, of one celestial body by another.
Ecliptic
Greek
ektos- outer, external, out of, out, outside; away from
-lipo- abandon, to leave [behind]
The apparent path of the sun traced along the sky
in the course of the year.
Ecocentrism
Greek
oikos- home, house
-centr- center
The view or belief that environmental concerns
should take precedence over the needs and rights
of human beings.
Ecocide
Greek
oikos- home, house
Destruction or damage to the environment, espe-
cially intentionally (e.g., by herbicides in war).
Ecogenetics
Greek/Latin
oikos- home, house
The study of the relationship between genetic fac-
tors and the nature of response to an environmental
agent.
Ecohazard
Greek/Arabic
oikos- home, house
-az zahr the gaming die, dice game
Any activity or substance that may constitute a
threat to a habitat or environment.
Ecology
Greek
oikos- house
bodies of knowledge
The science of the relationships between organ-
isms and their environments
Ecosystem
Greek/Latin
oikos- home, house
-systema the universe.
An ecological community together with its envi-
ronment, functioning as a unit.
Ecotaxis
Greek
oikos- home, house
-taxi arrangement, order; to put in order
The “homing” of recirculating lymphocytes to
specific compartments of peripheral lymphoid
tissues, with B cells going to B-dependent areas
and T cells to T-dependent areas.
Ecotone
Latin
oikos- home, house
-tonos tension, pressure
A transition region where adjacent biomes blend,
containing some organisms from each of the adja-
cent biomes plus some that are characteristic of,
and perhaps restricted to, the ecotone; this region
tends to have more species and to be more
densely populated than either adjacent biome.
The Eclipse That Stopped a War
Thales of Miletus (ca. 635–543 BC) is
regarded by many as the father of sci-
ence. He was a philosopher and an
astronomer living in a time before
Socrates. Unlike most philosophers of
this time, he put his intellect to use in
matters other than pure philosophy.
Although his motive probably was not
to become wealthy, he proved that by
applying what he had learned about the
natural world, he could succeed in
business and politics. And he did. He
was numbered among the Seven Sages
of Greece, those statesmen who were
known for their practical wisdom.
Thales studied the natural world and
its events. He believed that the world
was not created by supernatural forces,
but rather by naturally occurring
events. It was recorded by the historian
Herodotus of Halicarnassus (ca. 484–
425 BC) that Thales predicted the
occurrence of a total solar eclipse on
May 28, 585 BC. As it happened, that
eclipse ended a long and bloody war.
The warring factions, the Lydians and
the Medes, were in the sixth year of a
struggle with no end in sight. Right in
the middle of the battle of Halys, “the
day was turned into night,” and the bat-
tle was stopped and the war ended.

Effector 69
Ecotoxicologist
Greek
oikos- home, house
-toxikos- poison
-ologist one who deals with a specific topic
A specialist in the harmful effects of chemicals on
the natural environment.
Ectobiology
Greek
ektos- outside, external, beyond
bodies of knowledge
The study of the properties and biochemical con-
stitution of the cell surface and the specific
enzymes at the surface.
Ectocardia
Greek
plurals
The congenital displacement of the heart, either
inside or outside the thorax.
Ectoderm
Greek
-derm skin
Embryonic tissue layer that leads to the differen-
tiation of epidermal, nervous, and sensory organs
and tissues.
Ectognatous
Greek
-gnathos jaw
Derived characteristic of most insects, in which
mandibles and maxillae are not in pouches.
Ectohormone
Greek
-hormo- to rouse or to set in motion
carbonyl group
A parahormonal chemical mediator of ecological
significance that is secreted, largely by an organism
(usually an invertebrate) into its immediate envi-
ronment (air or water); it can alter the behavior or
functional activity of a second organism, often of
the same species as that secreting the ectohormone.
Ectolecithal
Greek
-lekithos egg yolk
Yolk for nutrition of the embryo contributed by
cells that are separate from the egg cell and are
combined with the zygote by envelopment within
the eggshell.
Ectomorphic
Greek
Referring to an individual characterized by having a
lean, slightly muscular build in which tissues
derived from the embryonic ectoderm predominate.
Ectoplasm
Greek
The cortex of a cell or that part of cytoplasm just
under the cell surface.
Ectoscopy
Greek
-skopein- see, view, sight, look at, examine
A diagnostic method based on observation of
chest and abdominal movements and said to be
capable of determining the outlines of the lungs
and of localized internal conditions.
Ectothermic
Greek
Having a body temperature derived by heat
acquired from the environment.
Edema
Greek
oid ma a swelling
The accumulation of excessive amounts of serous
fluids in the tissues or cavities within the body.
Effect
Latin
ex- outside, outward, out of, out; away from
-facere- to do; carry, bear, bring
The result or consequence of an action.
Effector
Latin
An organ or structure that responds as a result of
nervous stimulation.
e

70 Efferent
Efferent
Latin
-ent causing an action; being in a specific state;
within
Leading or conveying away from some organ—
for example, nerve impulses conducted away
from the brain, or blood conveyed away from an
organ; contrasts with afferent.
Efficiency
Latin
efficere- to effect
The ratio of useful work accomplished by a
machine compared to the total work put into it;
usually expressed as a percentage.
Effloresce
Latin
-florere flower; to blossom
To become covered by a crusty deposit when
water evaporates.
Ejecta
Latin
eicere- to throw out
Ejected matter, such as that from an erupting
volcano.
Ejection
Latin
eicere- to throw out
The act of ejecting or the condition of being ejected.
Elastic
Greek
elaunein- to beat out
Returning to or capable of returning to an initial
form or state after deformation.
Electricity
Greek
lektron- charge, electricity; dealing with positive
and negative charges
-ity state or quality
The flow of electrons in a circuit. The speed of
electricity is the speed of light (approximately
186,000 miles per second). In a wire, it is slowed
due to the resistance in the material.
Electrocardiograph
Greek
An instrument for recording the potential of the
electrical currents that traverse the heart and ini-
tiate its contraction.
Electrodialysis
Greek
-dia- through, across, point to point
-ly- loosening, dissolving, dissolution, breaking
A form of dialysis in which the application of cur-
rent to electrodes is used to separate substances or
compounds. Salt is removed from seawater in
large quantities in this manner.
Electrolysis
Greek
A process in which electrolytes are created by
splitting compounds using electric current.
Electrolyte
Latin/Greek
-lytesubstancecapableofundergoingdecomposition
A substance that when dissolved in a suitable sol-
vent becomes an ionic conductor.
Electromagnetic
Greek
-magnes- something that attracts (figurative sense)
Variation in electric and magnetic fields taking
place in regular, repeating fashion.
Electron
Greek
-on a particle
An elementary particle consisting of a charge of
negative electricity equal to about 1.602 × 10–19
coulomb and having a mass when at rest of about
9.109534 × 10–28
gram, or about 1/1836 that of a
proton.
Electronegativity
Greek
e
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e
e
e
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Emphysema 71
-negare- say no, deny
Property of an element that indicates how strongly
its atom attracts electrons in a chemical bond.
Electrophile
English
preference for
A chemical compound or group attracted to elec-
trons and tending to accept them.
Electrophoresis
Greek
-phoros- being carried, bearing
The movement of suspended particles in a fluid
under the influence of an electric field.
Electroweak
Greek/Middle English
lektron- charge, electricity; dealing with posi-
tive and negative charges
-weike pliant
Of or relating to the combination of the electromag-
netic and weak nuclear forces in a unified theory.
Element
Latin
elementum rudiment, first principle
A substance that cannot be separated into simpler
substances by chemical means.
Elimination
Latin
eliminat- to banish
A process by which wastes are removed from the
body.
Ellipse
Latin/Greek
en- in, at, onto
-leipein to leave
A plane curve, especially a conic section whose
plane is not parallel to the axis, base, or generatrix
of the intersected cone.
Elliptical
Greek
elleiptikos- of a leaf shape; in the form of an ellipse
or character of
Of, relating to, or having the shape of an ellipse;
containing or characterized by ellipsis.
Elongation
Latin
elongate- to make or grow longer
The act of making something longer or the condi-
tion of being made longer.
Elytra
Greek
elutron sheath
The thickened or leathery forewings of insects
such as beetles.
Embolism
Greek
em- in
Obstruction or occlusion of a blood vessel block-
ing the flow of blood.
Embryo
Greek
em- in
-bruein to be full, bursting
An organism in its early stage of development,
especially before it has reached a distinctively
recognizable form.
Embryogenesis
Greek
em- in
-bruein- to be full, bursting
The origin and development of the embryo;
embryogeny.
Emigration
Latin
e- out
-migrare- to move
The act or process of leaving an area or country to
live in another country.
Emission
Latin
mittere- to send out
-ion state, process or quality of
A substance discharged into the air, especially by
an internal combustion engine.
Emphysema
Greek
em- in, into, inward; within
-phusan to blow
A pathological condition of the lungs marked by
an abnormal increase in the size of the air spaces,
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72 Empirical
resulting in labored breathing and an increased
susceptibility to infection.
Empirical
Greek
empeirikos- doctor relying on experience alone
or character of
Referring to a formula that gives the simplest whole
number ratio of atoms of elements in a compound.
Emulsification
Greek
-mulg re- to milk out
Process of mixing two liquids that do not dissolve
in each other.
Emulsify
Latin
-fy cause; to become, make
To make into an emulsion.
Emulsion
Latin
A suspension of small globules of one liquid in a
second liquid with which the first will not mix.
Enantiomer
Greek
en- to cause to be
-anti- opposite
-mere considered apart from anything else; pure
Either of a pair of crystals, molecules, or com-
pounds that are mirror images but not identical.
Encephalitis
Greek
en- in, into, inward; within
Inflammation of the brain, usually caused by a
viral infection.
Encephalomalacia
Greek
Softening of brain tissue, usually caused by vas-
cular insufficiency or degenerative changes.
Endemic
Greek
-demo- population
A condition, such as a disease, that is prevalent in
a specific area.
Endergonic
Greek
endo- inside, within
-ergon- work
A chemical reaction requiring energy to obtain
the end products.
Endoabdominal
Greek
-abdomen- belly, venter, abdomen
or character of
Relating to tissues and other materials found
within the abdominal walls.
Endobenthos
Greek
-benthos deep; the fauna and flora of the bottom
of the sea
Organisms living within the sediment on the sea-
bed or lake floor.
Endocrine
Greek
endo- within
Glands that secrete hormones into the blood.
Endocytosis
Greek
The process of moving things to the inside of a cell.
Endoderm
Latin
-derma skin
In animals, the inner layer of embryonic tissue
from which the digestive organs develop.
Endoergic
Greek
-ergon- work
Occurring with absorption of energy. In biology,
the process by which heat is generated to main-
tain a constant body temperature.
e
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Enterocoel 73
Endognathous
Greek
-gnathos jaw
Ancestral character of insects, found in the orders
Diplura, Collembola, and Protura, in which the
mandibles and maxillae are located in pouches.
Endolecithal
Greek
-ekithos yolk
Yolk for nutrition of the embryo incorporated into
the egg cell itself.
Endometrium
Greek
-metra- womb
Mucous membrane lining the interior surface of
the uterus.
Endomorphic
Greek
An individual characterized by a significant
amount of soft tissue around the area of the abdo-
men; this fatty tissue develops from the embry-
onic endodermal layer.
Endoplasm
Greek
A central, less viscous portion of the cytoplasm
that is distinguishable in certain cells, especially
motile cells.
Endopod
Greek
-podos foot
Medial branch of a biramous crustacean appendage.
Endorphin
Greek
-morpheus- god of dreams
-in protein or derived from a protein.
A morphine-like substance secreted in the pitu-
itary gland to control pain and pleasure.
Endoskeleton
Greek
-skeletos hard
A supporting framework within the living tissues
of an organism.
Endosperm
Greek
-sperma seed
In flowering plants, storage tissue.
Endospore
Greek
-spora seed
A small asexual spore that develops inside the
cell of some bacteria and algae.
Endostyle
Greek
-sylos a pillar
Ciliated groove(s) in the floor of the pharynx of
tunicates, cephalochordates, and larval cyclos-
tomes, used for accumulating and moving food
particles to the stomach.
Endothermal
Latin/Greek
or character of
Pertaining to chemical reactions in warm-
blooded animals that generate heat for the main-
tenance of a constant internal environment.
Endothermic
Greek
Characterized by or causing the absorption of
heat.
Energy
Greek
en- in, at, onto
-ergon work
The capacity to do work; source of usable power;
vigorous exertion of effort.
Enneagynous
Greek
ennea- nine
-gynous in relation to the female organ of a plant
In botany, having nine pistils or styles in a flower.
Enterocoel
Greek
enteron- gut
-koiloma cavity

74 Enterocoelomate
A type of coelom formed by the outpouching of a
mesodermal sac from the endoderm of the primi-
tive gut.
Enterocoelomate
Greek
enteron- gut
-koiloma- cavity
An animal having an enterocoel, such as an echi-
noderm or a vertebrate.
Enthalpy
Greek
en- in, at, onto
-thalpien- to heat
The sum of the internal energy of a body and the
product of its volume multiplied by its pressure.
Entomology
Greek
entomos- cut from two, segmented
bodies of knowledge
The scientific study of insects.
Entropy
Greek
en- in, at, onto
-trope transformation
The tendency for all matter and energy in the uni-
verse to evolve toward a state of inert uniformity.
Environmentalist
French
environ- round about; encircle
-ment- state or condition resulting from a (speci-
fied) action
-al- of the kind of, pertaining to, having the form
or character of
-ist agent, specialist
Apersonwhoseekstoprotectthenaturalenvironment.
Enzyme
Greek
en- in, at, onto
-zume ferment, leaven
Produced by living cells that catalyze chemical
reactions in organic matter.
Eocene
Greek
eos- dawn
-kainos recent
An epoch of the lower Tertiary period, spanning
the time between 55.5 and 33.7 million years ago.
Eon
Greek
aion indefinitely long period of time
Longest period of geologic time.
Eosinophil
Greek
eos- dawn (color of), rose, red
-in- protein or derived from a protein
preference for
A granular bilobed leukocyte with coarse cyto-
plasmic granules that attract the red acid dye eosin,
a biological stain for studying cell structures.
Ephemeroptera
Greek
ephemeros- for a day
-pteron wing
Mayflies; fragile winged insects that develop
from aquatic nymphs and live as adults for only a
few days.
Epibenthos
Greek
epi- above, over, on, upon
of the sea
The community of organisms living at the surface
of the seabed or lake floor.
Epiblast
Greek
The outer layer of the blastula giving rise to the
ectoderm.
Epicardium
Greek
-ium quality of the relationship
The inner layer of the pericardium, a conical sac
of fibrous tissue that surrounds the heart.
Epicenter
Greek
-kentron center, sharp point
The point of the earth’s surface directly above the
focus of an earthquake.
Epicycle
Greek
-kyklos circle, wheel, cycle
A circle whose circumference rolls along the cir-
cumference of a fixed circle.

Epistome 75
Epidemic
Greek
epi- upon, above
-demos- people
A disease found among many people in an area; a
situation where an infectious disease develops
and spreads quickly through a population.
Epidendrous
Greek
-dendr- tree, treelike structure
Relating to organisms that grow or exist on trees.
Epidermis
Greek
-dermis skin
The outer epithelial layer of the external integu-
ment of the animal body that is derived from
embryonic epiblast.
Epididymis
Greek
-didumos twins, testicles
Long, narrow, convoluted tube on the top, poste-
rior aspect of either of the two testes; it is part of
the sperm duct system.
Epigastrium
Greek
-gastr- stomach, belly
-ium quality of the relationship
The part of the abdominal wall lying on or over
the stomach.
Epiglottis
Greek
-glotta tongue
The thin elastic cartilaginous structure located at
the root of the tongue that folds over the glottis to
prevent food and liquid from entering the trachea
during the act of swallowing.
Epinephrine
Greek
-nephros- kidneys
An endogenous adrenal hormone that increases
cardiac activity, dilates bronchial tubes, and stim-
ulates the production of glucose from glycogen.
Epiphyseal (line)
Greek
-phyein- to grow
or character of
Pertaining to or resembling the epiphysis; in long
bone development; the line that results when the
ossification process of the shaft meets with the
bony development at the end of a bone.
Epiphyte
Greek
-phuton plant having a (specified) characteristic
or habitat
A plant, such as a tropical orchid or a staghorn
fern, that grows on another plant upon which it
depends for mechanical support but not for nutri-
ents; also called aerophyte, air plant.
Epipod
Greek
-pous podos, foot
A lateral process on the protopod of a crustacean
appendage often modified as a gill.
Episode
Greek
-eisodios coming in besides, entering
An incident or event that stands out from the con-
tinuity of everyday life.
Episome
Greek
A genetic unit or gene that has the capacity to
exist outside of or independently of its host cell.
Epistasis
Greek
-histanai- to place; to stop
The suppression of a bodily discharge such as
urine. In genetics, the suppression of the expres-
sion of a gene by another gene.
Epistome
Greek
-stoma mouth
Flap over the mouth in some lophophorates that
bears the protocoel.

76 Epithethia
Epithethia
Greek
-thele- nipple
Latinizing plurals
Papillary projections of the epithelium that pene-
trate the underlying stroma of connecting tissue.
Epitope
Greek
-topos place, spot
A portion of a protein molecule that is the specific
target of an immune response.
Epizootic
Greek
-zoon- animal, animal-like
Affecting a large number of animals at the same
time within a particular region or geographic
area; used in reference to a disease.
Epoch
Greek
ep- time
-och fixed
Subdivision of a period on the geologic time scale.
Equation
Latin
aequi- equal, same, similar, even
-ion state, quality, or process of
A representation of a chemical reaction, usually
written as a linear array in which the symbols and
quantities of the reactants are separated from
those of the products by an equal sign, an arrow,
or a set of opposing arrows.
Equator
Latin
-or from
The imaginary great circle around the earth’s sur-
face, equidistant from the poles and perpendicu-
lar to the earth’s axis of rotation; it divides the
earth into the Northern Hemisphere and the
Southern Hemisphere.
Equilibrate
Latin
-libr- balanced, level; make even; weight
Having to maintain in or bring into equilibrium.
Equilibrium
Latin
-libr- balanced, level; make even; weight
A state of balance between opposing forces or
actions.
Equine
Latin
equus- horse
Of or belonging to the family Equidae, which
includes the horses, asses, and zebras.
Equinox
Latin
-noct night
Either of the two times during a year when the sun
crosses the celestial equator and when the day
and night are approximately equal in length.
Equipollent
Latin
-pollere- to be powerful
-ent causing an action; being in a specific state
Equal in force, power, effectiveness, or significance.
Equipotential
Latin
-potent- power; to be able
The work required to move a unit of positive charge,
a magnetic pole, or an amount of mass from a refer-
ence point to a designated point in a static electric,
magnetic, or gravitational field; potential energy.
Era
Latin
aera counters
The longest of the geological time periods, usually
marked by some catastrophic geological event.
Eremic
Greek
erem- lonely, solitary; hermit; desert
Pertaining to deserts or sandy regions.
Eremobiology
Greek
bodies of knowledge
The science of biology in arid ecological systems.

Esophagus 77
Eremophile
Greek
preference for
Organisms that survive and thrive in desert or
desertlike conditions.
Eremophyte
Greek
-phuton plant having a (specified) characteristic
or habitat
A plant species that has developed the adapta-
tions to live in arid, desertlike conditions.
Erg
Greek
ergon work
A small unit of work equal to the force of one
dyne acting over a distance of one centimeter.
Ergonomics
Greek
ergon- work
-nom- (nemein) to dictate the laws of; knowledge;
usage; order
The applied science of equipment design, as for
the workplace, intended to maximize productiv-
ity by reducing operator fatigue and discomfort.
Erogenous
Latin
eros- sexual love or sexual passion
Producing erotic feelings; often a reference to parts
of the body that are sensitive to sexual arousal.
Erosion
Latin
erosio- an eating away
The group of natural processes, including weath-
ering, dissolution, abrasion, corrosion, and trans-
portation, by which material is worn away from
the earth’s surface.
Eruciform
Latin
eruci- caterpillar
-forma having the form of
Applied to insect larvae, caterpillar-like; more or
less cylindrical with a well-developed head and
stumpy legs at the rear, in addition to the true tho-
racic legs. The caterpillars of butterflies and
moths are typical examples.
Erythroblast
Greek
eruthros- red
Immature red blood cells found within the red bone
marrow of mammals; they are typically nucleated.
Erythroblastosis
Greek
eruthros- red
-osis increase, formation
An abnormal presence of immature red blood
cells in the bloodstream.
Erythrocyte
Greek
eruthros- red
Red blood cell that contains hemoglobin and car-
ries oxygen from the lungs or gills to the tissues in
vertebrates.
Erythropoiesis
Greek
eruthros- red
-poiein- production, formation; to make
The process of the production of red blood cells
in the red bone marrow.
Erythropoietin
Greek
eruthros- red
-poiein- production, formation; to make
A chemical secreted by the kidney to regulate the
production of red blood cells.
Esophagoduodenostomy
Greek/Latin
ois- (pherein) to carry
-phagos- (phagein) to eat, eating
-duodeni- twelve each
-stoma- opening
Surgical removal of the stomach, followed by
connection of the esophagus to the duodenum.
Esophagus
Greek
ois- (future tense of pherein) to carry
-phagos- (phagein) to eat; eating
-us thing
A muscular, membranous tube extending from
the pharynx to the stomach.

78 Ester
Ester
German (from Latin)
essig vinegar
Any of a class of organic compounds correspond-
ing to the inorganic salts and formed from an
organic acid and an alcohol.
Esterification
Greek
äther- etherlike acid
-fication action, process, or quality of
A reaction involving a group of organic compounds
that causes the reagents (usually a carboxylic acid
and alcohol) to become an ester.
Estivation
Latin
estiv- dormancy in the summer
Theprocessofspendingthesummerinarestingstate.
Estrogen
Greek
oistros- frenzy; gadfly
Female sex hormones secreted by both the ova-
ries and the adrenal cortex.
Estuary
Latin
aestus- tide, surge
An arm of the sea that extends to meet the mouth
of a river.
Ethane
Greek
eth- organic functional group with two carbons
-aneorganiccompoundcontainingnomultiplebonds
An odorless alkane gas, C2H6.
Ether
Greek
aither upper air
Any of a class of organic compounds in which two
hydrocarbon groups are linked by an oxygen atom.
Ethnobotany
Greek
ethnos- people or races
-botan - fodder, plants
-onuma name
The study of the relationship between humans
and plants.
Etiology
Greek
aitia- cause
bodies of knowledge
The scientific study of the causes and origins of
diseases.
Etymology
Greek/Latin
etymon- true sense; earlier form of a word
bodies of knowledge
The study of the sources and development of words.
Eubacteria
Greek
eu- good, well; true
-bacter- microscopic organism
-baktron- staff, rod
plurals
Large group of bacteria having rigid cell walls.
Euglena
Greek
-glene eyeball
Any organism of the genus Euglena, found in
freshwater and characterized by chlorophyll, a
single flagellum, and a reddish “eyespot.”
Euhaline
Greek
-hal- salt
Term used with reference to normal sea water,
containing 30 to 40 parts per thousand salt;
applies to organisms thriving in this environment.
Eukaryote
Greek
-kairon nut; cell nucleus
An organism whose cells contain a distinct,
membrane-bound “true” nucleus.
Eumetazoans
Latin
-meta- later in time
-zoan animal
Animals with both tissues and symmetry.
Euphotic (zone)
Greek
-photos- light, radiant energy
Of, relating to, or being the uppermost layer of a
body of water that receives sufficient light for
photosynthesis and the growth of green plants.
e

Evapotranspiration 79
Eupnea
New Latin
eu- normal
-pnion breathing or breath
Normal, rhythmic, unlabored breathing rates.
Eurybaric
Greek
eury- wide, broad
-bar- weight, pressure
Applicable to animals adaptable to great differ-
ences in altitude.
Euryhalic
Greek
eury- wide, broad
-hal- salt
Able to tolerate a wide range of salinity; said of
organisms capable of withstanding widely vary-
ing concentrations of salt in the environment.
Euryhaline
Greek
eury- wide
-hal- salt
Able to tolerate wide ranges of saltwater
concentrations.
Euryphagous
Greek
eury- wide
An ecological term referring to an organism that
eats a large variety of foods.
Euryphotic
Greek
eury- wide, broad
-phot- light
Tolerant of a wide range of light intensity, typi-
cally measured between a forest and a field.
Eurypterid
Greek
eury- wide
-pteron- wing
Large, extinct scorpion-like arthropod considered
to be related to horseshoe crabs.
Eurytopic
Greek
eury- wide
-topos place
Refers to an organism or species capable of living
within a wide environmental range.
Eutrophic
Greek
eu- good, well, true
development
Having waters rich in mineral and organic nutri-
ents, causing plant life to proliferate, thereby
reducing the dissolved oxygen content and often
killing off other organisms.
Eutrophication
Greek
development
-ation action, process , or quality of
The process by which a body of water becomes
enriched in dissolved nutrients (such as phos-
phates) that stimulate the growth of aquatic plant
life, usually resulting in the depletion of dis-
solved oxygen.
Evacuate
Latin
-vacare- empty
To empty or send away; to eliminate or excrete
wastes from a living body.
Evagination
Latin
-vagina- sheath
An outpocketing from a hollow structure; to turn
a body part inside out.
Evaporation
Latin
vaporatus- steam, vapor
Vaporization of a liquid below its boiling point.
Evapotranspiration
Latin
-vaporatus- steam, vapor
-trans- across or through
-sp r re-to breath
The sum total of water loss due to evaporation
and plant transpiration.
i a

80 Evolution
Evolution
Latin
evolut- unrolling
The theory that the various types of animals and
plants have their origin in other, preexisting types
and that the distinguishable differences are due to
modifications in successive generations.
Excision
Greek
-cis- to cut
-ion state, process of
The process of cutting off something small by
surgery.
Excited
Latin
-ciere to set in motion
Being at an energy level higher than the ground state.
Excretion
Latin
-cernere- to separate
-ion state, process of
To separate and eliminate or discharge (waste) from
the blood or tissues or from active protoplasm.
Exfoliate
Latin
-folium- leaf
-ate of or having to deal with
To come off or separate into flakes, scales, or lay-
ers; mechanical weathering process in which
outer rock layers are stripped away, often result-
ing in dome-shaped formations.
Exobiology
Greek
bodies of knowledge
Study of life forms that possibly exist elsewhere
in the universe.
Exocytosis
Greek
-cyte- (kutos) sac or bladder that contains fluid
Theprocessofmovingthingstotheoutsideofacell.
Exopod
Greek
-podos foot
Lateral branch of a biramous crustacean appendage.
Exoskeleton
Greek
-skeletos dried up (body)
A hard outer structure, such as the shell of an
insect or crustacean, that provides protection or
support for an organism.
Exosphere
Greek
The outer layer of the thermosphere, extending
into space.
Exothermal
Greek
or character of
Characterized by or formed with the evolution of
heat.
Exothermic
Greek
Referring to a chemical reaction where heat is
released from the source.
Exotic
Greek
-otic state or condition of; condition of being
Strikingly, excitingly, or mysteriously different or
unusual; from another part of the world.
Expedition
Greek
-pedi- foot
A journey or excursion undertaken for a specific
purpose.
Experiment
Latin
experiri- to try
-ent causing an action or being in a specific state
A test under controlled conditions that is made to
demonstrate a known truth, examine the validity
of a hypothesis, or determine the efficacy of
something previously untried.

Eye 81
Exsiccated
Latin
-sicca- drying
Dried, especially in reference to soils that have lost
their moisture.
Extensor
Greek
-ten- to move in a certain direction; to stretch,
hold out
Any of various muscles that extend or straighten
some part of the body, especially a flexed arm or leg.
External
Latin
externus- outward
-al pertaining to, having the form or character of
Relating to, existing on, or connected with the
outside or an outer part; exterior.
Extinction
Latin
-stinguere- to quench
Ceasing of existence of a species.
Extraction
Greek
-trahere- to draw
To obtain from a substance by chemical or mechani-
cal action, as bypressure, distillation, or evaporation.
Extrusive
Latin
-trudere thrust
Igneous rock that forms when molten rock solidi-
fies above the surface.
Eye
Modern English
eghe resembling an eye shape
The development of a calm center of a storm.
Holland in the Seventeenth Century
Able to form a republic in the seventeenth century by
declaring its independence from Spain, Holland was
left to its own resources to either flourish or decline.
Thus, the economy of Holland was dependent on the
free-thinking, creative society of its day. Beginning
in that century, but associated more with the eigh-
teenth century, was the Age of Enlightenment, a
period characterized by reason rather than the tradi-
tions of the Dark Ages. This movement led to an
unparalleled optimism and to bold expressions of
philosophy, law, art, science, and government. The
Dutch embraced the Age of Enlightenment, which
eventually spread throughout Europe.
The formation of the Dutch East India Company
required the recruitment of skilled craftsmen to
build a fleet of ships capable of traveling great dis-
tances. The Dutch sailor-merchants sailed all over
the world and brought back the rarest of goods for
sale. Exploration became a part of the social fiber
of the Dutch people. Science, mathematics, and
philosophy flourished in Holland, where all free
thinkers were welcome to explore their passions.
There was little to fear from the Church, which still
held a grip over much of Europe. Men feared for
their lives when scientific reason clashed with the
accepted Church dogma. Thus seventeenth-century
Holland became home to many migrating scientists
and others who sought freedom to express their
ideas. In Amsterdam Anton Van Leeuwenhoek,
known as the father of microbiology, invented the
microscope during this period. It is said that his
microscopes, equipped with lenses that he himself
ground, were able to magnify well over 500 times
normal vision. Only a handful of the hundreds of
microscopes he crafted still exist today.
Christian Huygens crafted lenses for telescopes
and created a telescope that was over 5 meters long.
He speculated that the atmosphere of Venus caused
the planet to be covered by clouds. He observed the
patterns of rotation of planets, and he estimated
quite accurately the length of a Martian day. Huy-
gens was the first to recognize the rings of Saturn,
and he also discovered Titan, the planet’s largest
moon. These are only a few of the incredible dis-
coveries and inventions this scientist is responsible
for.
Countless people have been inspired over the
ages by this colony’s many explorers, adventurers,
craftsmen, statesmen, artists, mathematicians, and
philosophers. Even Albert Einstein was influenced
by a Portuguese-Jewish philosopher who lived in
Holland, Benedict (Baruch) Spinoza.

Famine
Latin
fames- hunger
A drastic, wide-reaching food shortage threaten-
ing the lives of an entire population.
Fault
Latin
fallere to deceive, fail
To shift so as to produce a fault.
Fecundity
Latin
fecund- fruitful, fertile
Refers to female animals: the faculty of reproduc-
tion; the capacity for bringing forth young; pro-
ductiveness. In botany, the faculty or power of
germinating.
Fermentation
Latin
fermentum- splits complex organic compounds
into simpler ones
A type of anaerobic pathway of ATP formation: it
starts with glycolysis, ends when electrons are
transferred back to one of the breakdown prod-
ucts or intermediates, and regenerates the NAD+
required for the reaction. Its net yield is two ATP
per glucose molecule degraded.
Ferroalloy
Latin
ferrum- iron; pertaining to, or containing iron
-alligare to bind
Any of various alloys of iron and one or more
other elements.
Ferrotherapy
Latin
ferrum- iron; pertaining to, or containing iron
-therapeuein to heal, cure; treatment
The treatment of disease with iron.
Fertilization
Latin
fertilis- to bear
The act or process of initiating the reproductive
process in sexual creatures by the union of an egg
and a sperm cell.
Fibrin
Latin
fibro-, fibr-, fibra- fiber; an elongated threadlike
structure
Large insoluble strands of protein that aid in the
clotting of blood.
Fibrinogen
Latin/Greek
structure
A blood plasma protein that turns into fibrin when
converted by thrombin during the blood-clotting
process.
Fibronectin
Latin/ Greek
structure

Flood 83
-nhkto- (Greek) swimming
A fibrous linking protein that functions as a retic-
uloendothelial mediated host defense mechanism
and is impaired by surgery, burns, infection, neo-
plasia, and disorders of the immune system.
Fibrosis
Latin
structure
The formation of excess fibrous tissue, usually as
an attempt to repair damaged tissue or as a reac-
tion to a trauma.
Field
Old English
feld field
A region of space characterized by a physical
property, such as gravitational or electromagnetic
force or fluid pressure, having a determinable
value at every point in the region.
Filial
Latin
fili- son, daughter, offspring
or character of
Of or relating to a generation or the sequence of
generations following the parental generation.
Filipodium
Latin
filum- thread
-podos- foot
A type of pseudopodium that is very slender and
may branch, but does not rejoin to form a mesh.
Filtration
Latin
filtrum- to put or go through a filter
A process in which mixtures are separated based
upon the size of particles that can fit through a filter.
Fimbriae
Latin
fimbriae thread, fringe
A thread or fringelike anatomical part of an
organ, such as the aperture to the Fallopian tubes.
Fine
Latin
finis utmost limit, end
In chemistry, refers to having a stated amount of
gold or silver in it. A gold or silver alloy that is
925/1000 fine is 92.5% gold or silver.
Fission
Latin
fissus- splitting
Act or process of splitting or breaking up into parts.
Fistula
Latin
fistula pipe
An abnormal duct or canal resulting from injury,
disease, or congenital disorder that extends from
the hollow of a body organ to the surface or to
another organ.
Fixation
Latin
fixus- to fasten
-ation action, process, or quality of
The process of conversion into a more reactive,
usable form.
Fjord
Old Norse
fjordhr inlet
A long, narrow, deep inlet of the sea between
steep slopes.
Flagellum
Latin
flagrum whip
A long, threadlike appendage; a whiplike extension.
Flammable
Greek
philogiston flammable
Describes a substance that is easily ignited and
capable of burning.
Flexor
Latin
flectere- to bend
Any muscle that bends a limb.
Flocculate
Latin
flocculus- tuft
To form into woolly, soft, or cloudlike masses; to
form compound masses, as a cloud or a chemical
precipitate.
Flood
Middle English
flud flowing water

84 Fluctuate
The overflowing of water on land that is usually
dry; a deluge.
Fluctuate
Latin
fluere- to flow, wave
To vary irregularly; to rise and fall in waves.
Fluid
Latin/Greek
A continuous, amorphous substance whose mole-
cules move freely past one another and that has
the tendency to assume the shape of its container;
a liquid or gas.
Fluke
Greek
plax flat surface
A flattened, digenetic trematode worm.
Fluorescence
Latin
-escentia state or process of
The process in which an atom releases energy in
the form of electromagnetic radiation.
Fluoroscope
Latin/Greek
An imaging device using x-rays to project a fluo-
rescent image on a screen.
Fluvial
Latin
fluvi- river, stream
or character of
Pertaining to rivers and river activities; found or
living in a river; produced by a river or stream.
Fluvioterrestrial
Latin
fluvi- river, stream
-terra- of or relating to the earth or its inhabitants
-ial of or relating to
Referstoinhabitingstreamsandthesurroundingland.
Flux
Latin
fluxus (past participle of fluere) to flow
The rate of flow of fluid, particles, or energy
through a given surface.
Foliaceous
Latin
folium- leaf
-aceous of or relating to a plant family
Belonging to, or having the texture or nature of
foliage or leaves; leaflike in form or made of
growth; composed of thin laminated layers, as
certain rocks.
Foraminiferan
Latin
forare- to bore; hole, an opening,
-ferre to bear
A member of the class Granuloreticulosea bear-
ing a shell with many openings.
Forbicolous
Greek
pherbein- to graze
-cola tiller, inhabitant
Living on broad-leaved plants; herbicolous.
Forbivorous
Greek/Latin
pherbein- to graze
-vorare- swallow, devour
Feeding on broad-leaved plants.
Force
Latin
fortis strong
A vector quantity that tends to produce an acceler-
ation of a body in the direction of its application.
Forensic
Latin
forensis- public
Relating to or dealing with the application of sci-
entific knowledge to legal problems.
Forest
Latin
foris outside
A dense growth of trees, plants, and underbrush
covering a large area.
Formation
Latin
format- shape, figure, appearance
The act or process of arranging something or of
taking form.
Formicary
Latin
formic- ant
A nest of ants or anthill.

Fundamental 85
Fossil
Latin
fossilis dug up
Having the characteristics of a fossil: preserved in
a mineralized or petrified form from a past geo-
logic age.
Fractal
Latin
frangere- to break
or character of
A geometric pattern that is repeated at ever smaller
scales to produce irregular shapes and surfaces that
cannot be represented by classical geometry.
Fractionate
Latin
frangere- to break
To separate a mixture by distillation, crystalliza-
tion, or other method into its ingredients or into
portions that have different properties.
Fractoluminescence
Latin
frangere- to break
-lumen- light
-ence the condition of
The emission of light from the fracture of a crystal.
Frequency
Latin
frequens- a crowd, throng
Thenumberofwavepeaksoccurringinaunitoftime.
Friction
Latin
fricare- to rub
The force generated opposite to the motion of an
object resulting from an interaction of surfaces.
Frigid
Latin
frigus- cold, frost
Referstoextremecold,withaverycoldtemperature.
Fructose
Latin
fructus- fruit
A very sweet sugar occurring in many fruits and
honey and used as a preservative for foodstuffs
and as a intravenous nutrient.
Fruit
Latin
fructus fruit
The ripened ovary or ovaries, together with acces-
sory parts, containing the seeds of a seed-bearing
plant and occurring in a wide variety of forms.
Fucivorous
Greek/Latin
phukos- rock lichen, seaweed
-vorare- to swallow, devour
Feeding or subsisting on seaweed and related sea
and ocean foods.
Fulcrum
Latin
fulcire to support
The point or support on which a level pivots.
Fumaroles
Latin
fumus- smoke, vapor
-ole little
Acrackorfissurethatreleasesgasesfromavolcano.
Fumatorium
Latin
fumus- smoke, vapor
-ate- to do, to make, to cause
-orium a place or a thing used for something
An airtight compartment in which vapor may be
generated to destroy germs or insects.
Fume
Latin
fumus smoke, vapor
Vapor, gas, or smoke, especially if harmful,
strong, or odorous.
Function
Latin
fungi- to do, perform, execute, discharge
The special, normal, or proper physiological activ-
ity performed by an organ or part.
Fundamental
Latin
fundus- bottom
fied) action
or character of
Of or relating to the foundation or base.

86 Fungal
Fungal
Latin
spongos- spongelike
or character of
Caused by a fungus, or relating to or having the
characteristics of a fungus.
Fungicide
Greek/Latin
spongos- spongelike
The destruction of fungi or something used to kill
fungi (spores).
Fungus
Greek
spongos- spongelike
-us singular
Eukaryotic organisms lacking chlorophyll and
vascular tissue. They range from unicellular to
multicellular. Many produce fruiting bodies.
Fusion
Latin
fundere- to melt
The joining into a single entity.

Galactose
Greek
galakt- milk
C6H12O6; one of the hextose sugars, it is found in
pectins and gums.
Galaxy
Greek
galakt- milk
plurals
Any of numerous large-scale aggregates of stars,
gas, and dust that constitute the universe, contain-
ing an average of 100 billion (1011
) solar masses
and ranging in diameter from 1,500 to 300,000
light-years. Also called nebula.
Gallbladder
Old English
galla- nutgall
-bla dre bladder
A small, hollow, saclike, muscular organ located
below the liver. It contains bile that is produced
by the liver and secretes the bile into the small
intestine to aid in the digestion of fats.
Gallimimus
Latin
gallus- rooster
-mimus mimic
A dinosaur whose fossil remains resemble a very
large rooster and that existed during the Late Cre-
taceous period in Mongolia.
Gametangium
Greek/Latin
gamet- husband or wife; to marry
-angeion- vessel
The reproductive organ of bryophytes, consisting
of the male antheridium and the female archego-
nium; a multichambered jacket of sterile cells in
which gametes are formed.
Gamete
Greek
gamein to marry
Either a male or female reproductive cell possess-
ing the haploid number of chromosomes.
Gametocyte
Greek
The mother cell of a gamete; that is, an immature
gamete.
Gametogenesis
Greek
The process in which production of gametes,
eggs or sperm, occurs.
Gametophyte
Greek
-phyte a plant
A stage in a plant’s life cycle during which eggs
and sperm are produced.
e

88 Ganglia
Ganglia
Greek
gangl- nerve bundle
plurals
Masses of nerve tissue containing nerve cells
external to the brain or spinal cord.
Gangue
French (from German)
gang lode
Worthless rock or other material in which valu-
able minerals are found.
Gas
Greek
chaos empty, space
Matter that has no fixed volume or shape; it con-
forms to the volume and shape of its container.
Gastrectomy
Greek
gastr- stomach, belly
Cutting out or removing the stomach.
Gastric
Greek
gastr- stomach
Pertaining to or having some characteristic of the
stomach.
Gastrodermis
Greek
-derma skin
Lining of the digestive cavity of cnidarians.
Gastroenteritis
Greek
-enteron- small intestine
Inflammation of the mucous membrane of the
stomach and intestines.
Gastromalacia
Greek
Softening of the walls of the stomach, usually
occurring after death.
Gastromegaly
Greek
-megaly large
Enlargement of the abdomen or the stomach.
Gastroplexy
Greek
-plexy fixation
Fixation of the stomach.
Gastropod
Greek
-podos foot
Any of a group of mollusks that have a broad disk-
like organ of locomotion on the ventral surface of
the body.
Gastroptosis
Greek/Latin
-ptosis downward, displacement, drooping, saggy
Downward displacement of the stomach.
Gastrovascular
Greek/Latin
-vas- vessel, duct
-cul- small, tiny
Describes the primary organ of coelenterates that
functions both in digestion and in the transporta-
tion of nutrients to all parts of an animal’s body.
Gastrula
Greek
-ula diminutive
An embryo at the stage following the blastula,
consisting of a hollow, two-layered sac of ecto-
derm and endoderm surrounding an archenteron
that communicates with the exterior through the
blastopore.
Gemmules
Latin
gemma- bud
-ule little, small
Asexual, cystlike reproductive unit in freshwater
sponges; formed in summer or autumn and capa-
ble of overwintering.
Genetic
Greek
gen- origin, birth
The branch of biology that deals with heredity,
especially the mechanisms of hereditary transmis-
sions and the variation of inherited characteristics
among similar or related organisms; the genetic
makeup of an individual, a group, or a class.

Gestation 89
Genome
Greek
gen- origin, birth
-ome group
Total number of genes in an individual.
Genotype
Greek
gen- origin, birth
-typos mark
The complete genetic constitution of an organism
or group as determined by the specific combina-
tion and location of the genes on the chromosome.
Genus
Latin
genus race
A group of related species with taxonomic rank
between family and species.
Geobios
Greek
ge- earth, world
-bios life, living organisms, or tissue
The total life of the land; that part of the earth’s sur-
faceoccupiedbyterrestrialorganisms;terrestriallife.
Geocentric
Greek
ge- earth, world
-kentron- a point or place that is equally distant
from the sides or outer boundaries of something;
the middle
Refers to early accepted position by scientists/
philosophers that the earth was the center of the
solar system and that all objects in the sky
revolved around the earth.
Geodesic
Greek
ge- earth, world
-daiesthai to divide
Describes the path an object will follow through
space and time in the absence of external forces.
Geography
Greek
ge- earth, world
The study of the earth and its features and of the
distribution of life on the earth, including human
life and the effects of human activity.
Geology
Greek
ge- earth, world
bodies of knowledge
Oforrelatingtothestudyoftheearth,includingsoils,
mineralogy, and the dynamics of the earth’s crust.
Geonyctitropism
Greek
ge- earth, world
-nycto- night; a relationship to darkness, dark
-trope- bend, curve, turn, a turning; response to
stimulus
Orientation movements in plants during darkness
in response to gravity.
Geophysiology
Greek
ge- earth, world
-phusio- form, origin, nature
bodies of knowledge
The study of the interaction among all organisms
living on the earth.
Geosynchronous
Greek
ge- earth, world
-synchron- at the same time
Refers to a geocentric orbit that has the same orbital
period as the sidereal rotation period of the earth.
Geothermal
Greek
ge- earth, world
-therm- heat, hot, warm
or character of
Of, relating to, or using the heat of the earth’s inte-
rior; also, to be produced or permeated by such heat.
Germination
Latin
germinare- to sprout
To begin or cause to sprout or grow.
Germovitellarium
Latin
germen- a bud, offshoot
-vitellus- yolk
Closely associated ovary and yolk-producing
structures in rotifers.
Gestation
Latin
gestare- to bear
Time during which a placental mammal develops
in a uterus.

90 Getter
Getter
Middle English
geta- to obtain
A chemically active substance such as magne-
sium that is ignited in vacuum tubes to remove
traces of gas, or any substance that is added to
another to remove traces of impurities.
Geyser
Icelandic
geysa to gush
A natural hot spring that intermittently ejects a
column of water and steam into the air.
Gibbous
Latin
gibbus bulging, hunch-backed, humped
Pertaining to swelling by a regular curve or sur-
face; protuberant; convex, as “the moon is gib-
bous between the half moon and the full moon.”
Gizzard
Latin
gigeria giblet, cooked entrails of poultry
The thickened part of the alimentary canal in
some animals (such as an insect or earthworm)
that is similar to the crop of a bird.
Glabrate
Latin
glab- smooth or hairless
Becoming smooth or glabrous from age.
Glacial
Latin
glacialis ice
Having an icelike form in its pure state at or just
below room temperature.
Gland
Latin
glans acorn
A term applied to a group of organs that secrete
chemicals used in other parts of the body.
Glaucoma
Greek
glaukos- gray
-oma swelling
A disease of the eye caused by increased pres-
sure, which can damage the optic nerve and result
in blindness.
Glitch
Yiddish/German
glitschn lapse, slip
A sudden change in the period of rotation of a
neutron star.
Globular
Latin
globus- globular mass
In biology, globe-shaped, having the form of a
ball or sphere (e.g., globular proteins)
Globular cluster
Latin/Old English
globus- globular mass
clyster bunches
In astronomy, a system of stars, generally smaller
in size than a galaxy, that is more or less globular
in conformation.
Glochidium
Greek
glokhis- point, barb of an arrow
-idion quality of relationship
Bivalved larval stage of freshwater mussels.
Glomerulus
Latin
glomer- ball
-ulus of, relating to, or resembling
Capillary network within glomerular capsule.
Glossus
Greek
glw^ssa the tongue
The muscular organ found in the mouths of verte-
brates. It is involved with the manipulation of
food during chewing, tasting, and swallowing,
and with speech.
Glottis
Greek
glotta/glossa tongue
The opening between the vocal cords in the larynx.
Glucagon
Greek
glukus- sweet, sweetness
-agein lead, drive
A peptide hormone secreted by pancreatic endo-
crine cells that raises blood glucose levels; an
antagonistic hormone to insulin.
Glucolytic
Greek
Pertaining to the metabolic breaking down of glu-
cose for the production of ATP occurring in the
cytoplasm of cells.

Gravitropism 91
Gluon
Latin
gluton- glue
-on subatomic particle
A hypothetical, massless, neutral elementary par-
ticle believed to mediate the strong interaction
that binds quarks together.
Glycogen
Greek
A polysaccharide that is the main form of carbo-
hydrate storage in animals and occurs primarily
in the liver and muscle tissue. It is readily con-
verted to glucose as needed by the body to satisfy
its energy needs. Also called animal starch.
Glycolysis
Greek
glykys- sweet
Initial reactions of both aerobic and anaerobic
pathways by which glucose is partially broken
down to pyruvate, with a net yield of two ATP.
Glycolysis proceeds in the cytoplasm of all cells,
and oxygen has no role in it.
Gnathostomes
Greek
gnathos- jaw
-stoma mouth
The group of vertebrates with distinct jaws.
Gonad
Greek
gonos procreation, genitals
A reproductive organ that produces sperm or eggs.
Gonadotropin
gonos- procreation, genitals
stimulus
Any one of three hormones released by either the
pituitaryglandortheplacenta.Thesehormonesstim-
ulate the gonads and control reproductive activity.
Gonangium
Latin
gonos- seed, procreation
-angeion diminutive of vessel
Reproductive zooid of hydroid colony (Cnidaria).
Gonophore
Latin
-pherein to carry
A small reproductive organ found in some
sponges.
Gonopore
Greek
-poros an opening
A genital pore found in many invertebrates.
Gradation
Latin
gradus- walk, step, take steps, move around
The leveling of a planet’s surface through weath-
ering, erosion, transpiration, and deposition of
rock debris by water, wind, and gravity.
Gradient
French (from Latin)
grade- a position in a scale of size, quality, or
intensity
-ient performing, promoting, or causing a spe-
cific action
The rate at which a physical quantity changes
with respect to a given variable.
Gradualism
Latin
gradus- walk, step, take steps, move around
The evolution of new species by the slow, steady
accumulation of small genetic changes occurring
over long periods of time.
Granuloma
Latin
granum- grain, seed
-oma community
A mass of inflamed granulation tissue, usually
associated with ulcerated infections.
Granum
Latin
granum grain, seed
A stacked, membranous structure within a chloro-
plast that contains the chlorophyll and is the site of
the light reactions involved in photosynthesis.
Gravitropism
Latin
gravis- heavy, weighty
stimulus
A turning or growth movement by a plant in
response to gravity.

92 Gravity
Gravity
Latin
An acceleration value related to the force attract-
ing two bodies.
Guanine
Spanish
huanu- the dung of sea birds or bats
A purine base, C5H5ON5, that is an essential con-
stituent of both RNA and DNA.
Gully
French
goulet the throat
Erosional features; deep channels found in sedi-
mentary layers, acted on by weathering.
Gustation
Latin
gustare- to taste
The sense of taste; the ability or the act of tasting.
Guttation
Latin
gutta- to drop
The exudation of water from leaves resulting
from root pressure.
Gymnosperm
Greek
gumnos- naked
-sperma seed
A plant whose seeds are not enclosed within an
ovary.
Gynecophoric
Greek
gyne- woman, female
-pherein to carry
Pertains to the groove in male schistosomes (cer-
tain trematodes) that carries the female.
Gynenosia
Greek
gyne- woman, female
-nosia disease
A disease occurring most often in females.
Gynoecium
Greek
gyne- woman, female
-oikos- house
Part of a flower that houses the female gameto-
phytes, the pistils.
Gyroscope
Greek
gyros- ring, compass
Rotating mechanism in the form of a universally
mounted spinning wheel that offers resistance to
turns in any direction.

Habitat
Latin
habitare to dwell
Area or environment where an organism or eco-
logical community normally lives.
Hadean
Greek
haides mythological subterranean world of the
departed spirits
Relates to the beginning of the earth’s formation,
when the surface was molten and forming, 4.5–
3.8 billion years ago (bya).
Hadron
English (from Greek)
hadros- thick
-on a particle
Any of a class of subatomic particles that are
composed of quarks and take part in the strong
interaction.
Halic
Greek
hal- salt
Pertaining to saline or saltlike conditions.
Halimetry
Greek
hal- salt
The measurement of the amount of saline matter
in solution.
Halite
Greek
hal- salt
A colorless, crystalline rock salt found in salt
marshes, dried desert floors, and mines.
Halobiotic
Greek
hal- salt
-bios- life, living organisms, or tissue
Refers to life in the sea, to organisms capable of
living in a marine environment.
Halogen
Greek
halos- disk of sun
Reactive, nonmetallic element in group 7A of the
periodic table.
Halolimnetic
Greek
hal- salt
-limn- lake
Pertaining to salt lakes; marine organism designed
to live in freshwater.
Halopexia
Greek
hal- salt
-pexia attaching to or fixation
The physiological retention of salt by the body.

94 Halophile
Halophile
Greek
hal- salt
preference for
A microorganism requiring a high concentration
of salt for optimal growth.
Halophobe
Greek
hal- salt
-phobos fear
Any creature that is intolerant of saline life.
Harmonics
Greek
harmonikos- harmony
Tones whose frequencies are whole-number mul-
tiples of the fundamental; also referred to as fun-
damental frequencies.
Haustoria
Latin
haurire- to drink
plurals
The hyphae that invade the cells of a host to
absorb nutrients.
Heat
Old English
hete hot
A form of energy associated with the motion of
atoms or molecules.
Helictite
Greek
helix- spiral
-ite a part of or product of
Thin crystal strains that resemble flowers and are
found in clusters on cave ceilings.
Heliocentric
Greek
helio- sun
-kentron-apointorplacethatisequallydistantfrom
thesidesorouterboundariesofsomething;themiddle
Describes the nature of the solar system, with the
sun located in the center and the planets orbiting
around it.
Hematemesis
New Latin
haimat- blood
-emesis vomit
The presence of blood or blood cells in vomit.
Isaac Newton
Beginning in 1665 and continuing into
1666, the Great Plague of London dev-
astated the English population. This
catastrophic disease, most likely
bubonic plague, killed over 75,000 in
that country. Because of these condi-
tions, a relatively young undergraduate
student at Cambridge University in
London was sent home. At Woolthorpe,
the town where he was born, Isaac New-
ton would live as a recluse during that
year, far from the death and dying in
London.
With the exception of Einstein’s
miracle year of 1905, few other single
years in history have had such a dra-
matic impact on science, discovery, and
the progression of thought. In the 18
months during his time off from school,
Isaac Newton laid some of the ground-
work for the study of optics and the
nature of light, he invented calculus,
and he put forth some of the essential
elements for his theory of universal
gravitation.
Isaac Newton was another major fig-
ure of the scientific revolution. Like
most other great thinkers of his day, he
was, for a time, fascinated by mysti-
cism, astrology, and mathematics. He
sought harmony in the universe through
mathematics.
Among Newton’s theories was the
idea that gravity is universal. He postu-
lated that if the earth’s gravitational
attraction held the moon in its orbit,
then this same force was responsible for
keeping other planets in their orbits as
well. The orbital paths of planets were
affected, in part, by the gravitational
attraction of the sun. Newton, unlike
Kepler, was able to mathematically
prove Kepler’s laws of planetary
motion.
Isaac Newton is known for his three
laws of motion.
• Newton’s first law, the law of
inertia, states that an object at rest
tends to stay at rest and that an
object in motion tends to stay in
motion unless acted upon by a net
external force.

Hemophilia 95
Hematocrit
Greek
haimat- blood
-krites judge
The instrument used to determine the ratio of the
volume occupied by blood cells to the total vol-
ume of blood.
Hematolysis (hemolysis)
Greek
haimat- blood
The lysing or breakdown of erythrocytes (red blood
cells) with the subsequent release of hemoglobin.
Hematuria
New Latin
haimat- blood
-uria urine
The presence of blood or blood cells in urine
Hemimetabolous
Greek
hemi- half
-metabole- change
Refers to gradual metamorphosis during the
development of insects, without a pupal stage.
Hemiptera
Greek
hemi- half
-pteron wing
Insect order for true bugs; wingless or four-
winged bugs that include such insects as bedbugs
and chinch bugs.
Hemisphere
Greek
hemi- half
A half of a sphere.
Hemocoel
Greek
haima- blood
-koilos cavity
A cavity or series of spaces between the organs of
most arthropods and mollusks through which
blood circulates.
Hemodialysis
Greek
haimo- relating to blood or blood vessels
-dia- through, across, apart
A medical procedure for removing metabolic
waste products from the blood.
Hemoglobin
Latin/Greek
-globulus- globule
An iron-containing respiratory pigment occur-
ring in vertebrate red blood cells and in blood
plasma of many invertebrates; a compound of an
iron porphyrin heme and a protein globin.
Hemolymph
Latin/Greek
-numphe clear fluid; water nymph, young bride
Fluidinthecoelomorhemocoelofsomeinvertebrates
that represents the blood and lymph of vertebrates.
Hemolysis (hematolysis)
Greek
The destruction of red blood cells, leading to the
release of hemoglobin from the cells into the
blood plasma.
Hemophilia
Greek
preference for
• Newton’s second law states that
force = mass × acceleration. That
is, the acceleration produced by a
net force on an object is directly
proportional to the magnitude of
the net force and is inversely pro-
portional to the mass.
• Newton’s third law states that for
every action there is an equal and
opposite reaction.
On July 5, 1687, Isaac Newton pub-
lished his seminal three-volume work,
Philosophiae Naturalis Principia
Mathematica, which is Latin for Mathe-
matical Principles of Natural Philoso-
phy. His text is sometimes referred to as
Principia or Principia Mathematica. It
contains his groundbreaking principles
for the mechanics of the universe, his
three laws of motion, and his law of uni-
versal gravitation.
Sir Isaac Newton died on March 20,
1727, in London.

96 Hemorrhage
plurals
A group of hereditary bleeding disorders charac-
terized by a deficiency of one of the factors neces-
sary for coagulation of the blood.
Hemorrhage
Greek
-rhegnynai to break, burst
Excessive discharge of blood from the blood ves-
sels; profuse bleeding from a ruptured blood vessel.
Hemorrhoid
Greek
-rhein- to flow
-oid (oeides) resembling, having the appearance of
A mass of dilated blood vessels located in the
anus; the dilated vessels cause pain and itching.
Hepatitis
Latin
hepat- liver
A disease or condition marked by inflammation
of the liver.
Hepatomalacia
Greek
hepat- liver
A disease or condition of the liver marked by dis-
tinct softening of the fleshy tissue of the liver.
Hepatonecrosis
Greek
hepta- liver
-necr- death
Death of liver cells, usually caused by either a
pathogenic organism or a toxic substance.
Hepatorrhexis
Greek
hepta- liver
-orrhexis, -rrhexis rupture of an organ or vessel;
a breaking forth, bursting
The rupturing of the liver occurring as a result of
injury or disease.
Heptad
Greek
heptados group of seven
An element, atom, or radical that has a valence of 7.
Herbicide
Latin
herba- grass, green crops
Any chemical agent that is toxic to some or all
plants and is used to destroy unwanted vegetation.
Herbivore
Latin
-vorare to devour
Any organism subsisting on plants.
Heredity
Latin
hered- heir
The transmission of qualities from ancestor to
descendant through the genes.
Hermaphrodite
Greek
hermes- Hermes, Greek god of boundaries
-aphrodite Aphrodite, Greek goddess of love and
beauty
An animal or plant species that normally exhibits
both male and female sex organs.
Hernia
Latin
herni- protruded viscus; rupture
plurals
The protrusion of a bodily organ through a nor-
mally intact supporting wall-like structure.
Heterocercal
Greek
heteros- different
-kerkos- tail
or character of
In some fish, having or referring to a tail with the
upper lobe larger than the lower, and the end of
the vertebral column somewhat upturned in the
upper lobe, as in sharks.
Heterochrony
Greek
heteros- different
-khronos- time
Evolutionary change in the relative time of
appearance or rate of development of characteris-
tics from ancestor to descendant.
Heterocyst
Greek
heteros- different
-cyst (kustis) sac or bladder containing fluid

Holeuryhaline 97
A large, thick-walled, transparent cell that occurs
at intervals along the filaments of certain cyano-
bacteria.
Heterodont
Greek
heteros- different
-odous tooth
Having teeth differentiated into incisors, canines,
and molars for different purposes.
Heterotroph
Greek
heteros- different
-trophos (trophein) to nourish, food; nutrition;
development
An organism that obtains both organic and inor-
ganic raw material from its environment in order
to survive.
Heterozygote
Greek
heteros- different
-zygoun to yoke
An organism that has different alleles at a partic-
ular gene locus on homologous chromosomes.
Hexabasic
Latin
hexa- six
-bas- low
Relates to having six hydrogen atoms that can be
replaced by basic atoms or radicals.
Hexactinellida
Greek
hexa- six
-aktin- ray
-ella little
A siliceous sponge characterized by glassy spicules.
Hexagonal
Greek
hexa- six
-agon- a violent, intense struggle
or character of
Having three equal axes intersecting at angles of
60 degrees in one plane, and one axis of variable
length that is perpendicular to the others.
Hexahedron
Greek
hexa- six
-hedron face
A Platonic six-sided solid; a cube.
Hexamerous
Greek
hexa- six
-meros part
Having six parts; specifically, symmetry based on
six or multiples thereof.
Hibernation
Latin
hibern- winter
The process of spending the winter in a resting state.
Hilum
Latin
hilum trifle
A notch on the medial surface of the kidney
where blood vessels enter and leave the kidney.
Hippocampus
Latin
hippos- riverine
-kampos sea monster
Composed of gray matter, this ridge on the floor
of the lateral ventricles of the brain is responsible
for memory.
Hippopotamus
Greek
hippos- riverine
-potamios horse
Chiefly aquatic mammal with an extremely large
head and mouth, bare and very thick grayish skin,
and short legs.
Histochemistry
Greek
histos- web, tissue
-chemo- (khemeia) chemical; alchemy
The science dealing with the chemical composi-
tion of the tissues of the body.
Histology
Greek
histos- web, tissue
bodies of knowledge
The study of the microscopic structures of tissues.
Histone
Greek
histos- web, tissue
carbonyl group
Any of a group of strongly basic low-molecular-
weight proteins that combine with nucleic acid to
form nucleoproteins.
Holeuryhaline
Greek
holos- complete, whole, entire, all, full

98 Holistic
-eury- wide
-hal- salt
Refers to organisms that freely inhabit freshwa-
ter, sea water, and brackish water.
Holistic
Greek
-ist- one who performs an action
Describes an approach to medical care that
emphasizes the study of all aspects of a person’s
health, including physical, psychological, social,
economic, and cultural factors.
Holocene
Greek
-kainos recent
An epoch of the Quaternary period, spanning the
time from the end of the Pleistocene to the present.
Holoenzyme
Latin
-en- in, at, onto
-zume ferment, leaven
A fully active, complex enzyme, composed of a
protein and a coenzyme.
Holometabolous
Greek
-meta- between, after, beyond, later
Pertains to complete metamorphosis during
development.
Holophytic
Greek
-phyt- plant
Relates to the process that occurs in green plants
and certain protozoa involving synthesis of carbo-
hydrates from carbon dioxide and water in the pres-
ence of light, chlorophyll, and certain enzymes.
Holozoic
Greek
-zoikos- of animals
Describes a type of nutrition involving ingestion
of liquid or solid organic food particles.
Homeopathy
Greek
homeo- same, like, resembling, sharing, similar,
equal
-pathos- feeling, sensation, perception
A method of disease treatment that involves the
administration of small doses of chemicals that, if
given in large amounts, would produce symptoms
in healthy people that are similar to those found in
people with the disease.
Homeostasis
Greek
equal
Tendency of an organism to maintain internal
equilibrium of temperature and fluid content, for
example, by regulation of its bodily processes.
Homeothermic
Greek
equal
Having a nearly uniform body temperature.
Hominid
Latin
homo/homonis- man
A member of the family Hominidae; human
beings are the only surviving species.
Homocercal
Greek
(h)omos- (combining form) one and the same,
common
-kerkos tail
Having or referring to a tail with the upper and
lower lobes symmetrical and the vertebral col-
umn ending near the middle of the base, as in
most teleost fish.
Homogeneous
Greek
common
-genus offspring, kind
Of the same or similar nature or kind.

Hydra 99
Homologous
Greek
common
-logos word, proportion
Havingthesameorsimilarproportionsorcharacter-
istics. In genetics, having the same gene sequence
on two different chromosomes.
Homoplasy
Greek
common
-plasy growth or development of
Independent evolution of similar or identical
characteristics through convergence or parallel
evolution.
Homozygote
Greek
common
-zugoun to yoke
Organism having the two genes at corresponding
loci on homologous chromosomes identical for
one or more loci.
Horizontal
Greek
horos- (horizein) to limit; boundary
or character of
Refers to the axis parallel to the horizon (side by
side); of or near the horizon; relating to the horizon.
Hormone
Greek
horman that which sets in motion; to urge on
Substances produced by a gland or tissue, then
transported by the blood to effect physiological
activity and regulate development.
Horology
Greek
horo- hour, period of time, season, time
bodies of knowledge
The science of measuring time.
Horoscope
Greek
horo- hour, period of time, season, time
-skopos observer
An astrological prediction based on observations
of the positions of celestial objects.
Horse
Old English
hors horse
Common name given to species of the genus Equus.
These mammals are characterized by having long
legs, short-haired coats, long tails, and hooved feet.
Humerus
Latin
humer- shoulder, upper arm
-us thing
The long bone of the arm or forelimb, extending
from the shoulder to the elbow.
Humidity
Latin
humidus- moist, wet
The amount of water vapor or moisture in the air.
Humoral
Middle English
humor- fluid
or character of
Of or pertaining to the fluid of a body.
Humus
Latin
humus soil
Partially decomposed organic matter consisting of
both plant and animal remains, rich in nutrients and
capable of holding significant amounts of water.
Hyaline
Greek
hualos- glass
A clear, homogeneous, glassy substance nor-
mally found in cartilage, vitreous humor, mucin,
and glycogen, and pathologically found in the
degeneration of tissues and cells.
Hybrid
Latin
hybrida mongrel
An offspring of two animals or plants of different
races, breeds, varieties, species, or genera.
Hybridization
Latin
hybrida- mongrel
The act of cross-breeding various species or sub-
species of organisms.
Hydra
Greek
hydra of or having to do with water
In astronomy, the largest constellation, winding
across more than a quarter of the sky.

100 Hydranth
Hydranth
Greek
hydr- of or having to do with water
-anthos flower
Nutritive zooid of hydroid colony.
Hydrate
Greek
A compound that contains a specific ratio of water
to ionic compound.
Hydration
Greek
In chemistry, the combination of water and another
substance to obtain a single product. In earth sci-
ence, a form of chemical weathering caused by the
expansion of certain minerals as they absorb water.
Hydraulic
Greek
-aulos characterized by having a hollow way;
tube, pipe
Of or relating to water or other liquid in motion.
Hydrocarbon
Greek
-carbon coal, charcoal
Organic compounds containing hydrogen and
carbon only.
Hydrocephalus
Greek
-us thing
A usually congenital condition in which an
abnormal accumulation of fluid in the cerebral
ventricles causes enlargement of the skull and
compression of the brain.
Hydrocoel
Greek
-koilos hollow
Second or middle coelomic compartment in echi-
noderms; the left hydrocoel gives rise to the
water-vascular system.
Hydrocoral
Greek
-korallion coral
Any of certain members of the cnidarian class
Hydrozoa that secrete calcium carbonate and
resemble true corals.
Hydroformylation
-formyl- the negative univalent radical HCO
The process by which an –H and a –CHO are
added across a carbon-carbon double bond. An
aldehyde synthesis process.
Hydrogenation
Greek
Theprocessofcombiningasubstancewithhydrogen.
Hydrogeology
Greek
-ge- earth
bodies of knowledge
The branch of geology that deals with the occur-
rence, distribution, and effects of groundwater.
Hydrology
Greek
bodies of knowledge
The study of the properties, distribution, and
effects of water on the surface of the earth, the
atmosphere, and the earth’s substrate.
Hydrolysis
Greek
Decomposition of a chemical compound by reaction
with water, such as the dissociation of a dissolved
salt or the catalytic conversion of starch to glucose.
Hydrometer
Greek
to measure
An instrument used to determine specific gravity.
Hydropenia
Greek
A condition or disorder that results in a reduction
of water.

Hypertension 101
Hydrophobic
Greek/Latin
-phob- fear, lacking an affinity for
Describes something that is repelled by water or
tends not to combine with or dissolve in water.
Hydrophyte
Greek
-phyte plant
A plant adapted to grow in water; a water lily.
Hydroplane
Greek
-plane surface
To skim along the surface of water.
Hydroponic
Greek
-pono- work
Pertains to growing plants without soil in nutrient-
enriched water.
Hydropower
Greek/Latin
-potis able, powerful
Electrical energy produced by falling or flowing
water.
Hydrosphere
Greek
The water on the earth’s surface.
Hydrostatic
Greek
Relating to fluids at rest or to the pressures they
exert or transmit.
Hydrothermal
Greek
Relating to hot water; magmatic releases are rich
in water.
Hydrozoan
Greek
-zoon animal, animal-like
Any of a group of freshwater coelenterates
including hydras, hydroids, hydrocorals, and
siphonophores.
Hygrometer
Greek
hygr- wet or moist
to measure
An instrument that measures humidity.
Hygroscopic
Greek
hygr- wet, moist
-scopion- to look at, examine
Refers to a substance that easily absorbs water
from the air to become a hydrate.
Hymen
Greek
humen thin skin, membrane
A membranous tissue fold that either partially or
completely covers the vaginal orafice.
Hymenoptera
Greek
humen- thin skin, membrane
-pteron wing
Order of insects characterized by thin, membra-
nous wings. Most have two pairs of wings, with
the first being considerably larger than the sec-
ond. Includes wasps, bees, and ants.
Hyoid
Greek
hu- upsilon, Greek letter U
Relating to the hyoid bone.
Hyperglycemia
Greek
hyper- above, high
-glyco- sugar
-emia the condition of having (a specific thing) in
the blood
Abnormally high blood sugar.
Hyperpnea
Greek
hyper- over, beyond
-pnein breathing or breath
Abnormally deep or rapid breathing.
Hypertension
Greek
hyper- over, beyond
-tens- stretching; physiological imbalance
Abnormally high blood pressure.

102 Hyperthermic
Hyperthermic
Greek
hyper- over, beyond
Having the characteristics of or relating to a con-
dition of unusually high body temperature.
Hypertonic
Greek
hyper- over, beyond
-ton- tension
Having the higher osmotic pressure of two solutions.
Hyperventilation
Greek
hyper- over, beyond
-ventilare- to fan
A pulmonary ventilation rate that is higher than what
is necessary for normal pulmonary gas exchange.
Hyphae
Greek
huphe web
Threadlike filaments found in the mycelium of a
fungus.
Hypocalcemia
Greek/Latin
hypo- under, below, beneath, less than, too little,
deficient
-calc- calcium
-emia the condition of having a (specific thing) in
the blood
A deficiency of calcium in the blood.
Hypochondria
Greek
deficient
-khondr- grain, any small rounded mass; carti-
lage, gristle, granule, or a relationship to cartilage
plurals
A disorder characterized by a misinterpretation of
physical signs that leads to the belief that one has a
serious disease even though repeated evaluations
show no indications of any physical disorder.
Hypodermis
Greek/Latin
deficient
-derma skin
The cellular layer lying beneath and secreting the
cuticle of annelids, arthropods, and certain other
invertebrates.
Hypoglossal
Greek
deficient
-gloss- tongue
or character of
Of or relating to the area under the tongue.
Hypognathous
Greek
deficient
-gnathos jaw
Pertains to having the head directed vertically and
the mouthparts directed ventrally.
Hypokalemia
Greek
deficient
-kali- potassium
the blood
A deficiency of potassium in the blood.
Hypostome
Greek
deficient
-stoma mouth
Name applied to the structure in various inverte-
brates, such as mites and ticks, that is located at
the posterior or ventral area of the mouth; eleva-
tion supporting the mouth of a hydrozoan.
Hypotenuse
Greek
deficient
-teinein to stretch
The line segment stretched under the right angle;
the line opposite the right angle in a right triangle.
Hypothalamus
Greek
deficient
-thalamos inner chamber, bedroom
The region of the brain situated below the thala-
mus and above the pituitary gland, which acts as a
control center for the autonomic nervous system
and for hormonal activity.
Hypothermia
Greek
deficient

Hystolytic 103
plurals
A condition in homeothermal organisms marked
by a drop to a temperature below normal.
Hypothesis
Greek
deficient
-tithenai- to put or place
An assertion made as a possible explanation for a
problem.
Hypothetical
Greek
deficient
-tithenai- to put or place
-alis of, related to
Refers to a situation or setting based on or relat-
ing to a hypothesis.
Hypotonic
Latin/Greek
deficient
-ton- tension
In chemistry, refers to a situation where one solu-
tion’s osmotic pressure is lower than that of
another solution.
Hypoxia
Greek
deficient
-ox- acid, acidic
plurals
A disorder that causes a reduction in the oxygen
supply to tissues.
Hysterectomy
Greek
hustera- uterus, womb
Partial or complete surgical removal of the uterus.
Hysteroptosis
Greek
hyster- the womb or uterus; hysteria
-pto- fall, a falling down of an organ; drooping,
sagging; corpse
The sagging or prolapsing of the female uterus.
Hystolytic
Greek
histos- web, tissue
Pertaining to the degeneration of tissues.

Ichthyologist
Greek
ichthus- fish
A scientist who studies the biology of fish.
Ichthyology
Greek
ichthus- fish
bodies of knowledge
Branch of zoology that deals with the study of fish.
Icosahedron
Greek
icosa- twenty
-hedron face
A Platonic solid with twenty faces.
Ideal
Latin
idea- a plan, scheme, notion, or method
or character of
Conforming to an ultimate form or standard of
perfection or excellence.
Igneous
Latin
ignis- fire
Refers to molten rock that cools and solidifies.
Ileum
Latin
ileum groin, flank
The terminal end of the small intestine; it extends
from the jejunum to the ileocecal sphincter.
Iliocostal
Latin
ilia- groin, flank
-costo- rib
or character of
Relating to the ilium and ribs.
Image
Latin
imago image
In optics, the likeness of an object produced by
the use of a lens or group of lenses.
Imbibition
Latin
in- in, into, toward, against, on, upon
-bib- drink
Adsorption of water to internal surfaces of an
organism, leading to swelling.
Immigrate
Latin
-migrare- to go into, to depart
To enter and settle in a country or region to which
one is not native.
Immiscible
Latin

Inertia 105
-miscere- to mix
-ible capable
Refers to that which cannot undergo mixing or
blending.
Immunotherapy
Latin/Greek
immunis- not affected by a given influence; unre-
sponsive
-therapeuein to treat medically
Treatment of disease by inducing, enhancing, or
suppressing an immune response.
Impedance
Latin
impedire to hinder motion on foot
A measure of the total opposition to current flow
in an alternating current circuit, made up of two
components: ohmic resistance and reactance.
Impenetrability
Latin
im- not
-penitus- deeply, permeate
A property of matter where no two objects can
occupy the same space at the same time.
Impulse
Latin
impellere to impel
The product obtained by multiplying the average
value of a force by the time during which it acts.
The impulse equals the change in momentum
produced by the force during this time interval.
Inactive
Latin
-agere to drive or do
Not active; in biology, refers to a condition during
which metabolism is marked by a reduction of
activity, possibly because of an infection.
Incandesce
Latin
-candescere become white hot
To glow or cause to glow with heat.
Incisor
Latin
-caedere- to cut
A tooth for cutting or gnawing, located at the
front of the mouth in both jaws.
Incline
Latin
-klinein to lean, sloping
A slant; deviation from the horizontal or vertical.
Incubation
Latin
in- in, into, toward, against, on , upon
-cubare- to lie down on
Maintenance of optimal conditions for growth
and development.
Indigenous
Latin
-genus- birth, origin, kind
Pertaining to a group of organisms native and
original to a region.
Induction
Latin
-ducere- to lead
-tion action, process or quality of
The production of magnetism or electromotive
force, or the separation of charge from a body by
a neighboring body not in contact with it.
Inductor
Latin
-ducere- to lead
A coil of wire that generates a magnetic field
when a current is passed through it.
Inelastic
Greek
-elaunein- to beat out
Refers to a type of collision in which two objects
remain attached after the collision.
Inert
Latin
-aras skill
Unable to move or act; not readily reactive with
other elements.
Inertia
Latin
iners- idleness
plurals

106 Infectious
The tendency of a body to resist acceleration; the
tendency of a body at rest to remain at rest, or of a
body in straight-line motion to stay in motion in a
straight line unless acted on by an outside force.
Infectious
Latin
-facere- to make, do, build, cause, produce; form-
ing, shaping
Pertaining to a contagious disease capable of
spreading rapidly to others.
Inference
Latin
-ferre- to bear
The act of passing from one proposition, statement,
or judgment considered true to another, whose truth
is believed to follow from that of the former.
Inferno
Latin
infernus hell, lower, underground
In astrophysics, a unit for describing the tempera-
ture inside a star. One inferno is approximately
one billion degrees celsius.
Inflammation
Latin
-flamma- flame
-ation action, process, or quality of
A localized defensive reaction of body tissue to irri-
tation, damage, or infection; characterized by pain,
redness, swelling, and sometimes loss of function.
Inflation
Latin
-flare- to blow
In astronomy, an extremely brief phase of ultra-
rapid expansion of the very early universe.
Influenza
Latin
-fluere- to flow, wave
-za quality or state
A human respiratory infection of undetermined
cause.
Infraciliature
Latin
infra- inferior to, below, or beneath
-cilia- eyelashes
-ure act, process, condition
The organelles just below the cilia in ciliate
protozoa.
Infracostal
Latin
-costo- rib
or character of
Pertaining to or referring to a region below the
ribs.
Infrasonic
Latin
-sonus- sound
Generating or using waves or vibrations in fre-
quencies below that of audible sound.
Inherit
Latin
-hereditare to inherit
To acquire or express traits or conditions through
transmission of genetic material from parents to
offspring.
Initiator
Latin
initium- beginning
A substance or chemical that begins a reaction
but is consumed or chemically changed in the
reaction.
Inorganic
Latin
-organon- instrument
Composed of nonliving matter.
Insect
Greek
-secare- to cut up
Any member of the class Insecta. All organisms
in this class are segmented into three body parts,
have an exoskeleton, and have three pairs of
legs.
Insecticide
Greek
in- in, into, toward, against, on , upon
-secare- to cut up

Intermolecular 107
Type of pesticide that controls or eliminates insects
that adversely affect plants, animals, or people.
Insectivore
Greek/Latin
-secare- to cut up
-vorare to eat, devour
Animal or plant that feeds on insects.
Instinct
Latin
instinctus impulse
A complex pattern of innate behavior.
Insulator
Latin
insula- island
-or a conition or property of things or persons
A material that insulates or retards the transfer of
energy, especially a nonconductor of sound, heat,
or electricity.
Insulin
Latin
insula- island
A hormone secreted by the islets of Langerhans in
the pancreas. Insulin is essential for the proper
uptake and metabolism of sugar.
Integument
Latin
-tegere to cover
A natural outer covering or coat, such as the skin
of an animal or the membrane enclosing an organ.
Interaction
Latin
inter- between, among
-agere- to do
Any of four fundamental ways in which elemen-
tary particles and bodies can influence each other,
classified as strong, weak, electromagnetic, and
gravitational.
Intercellular
Latin
-cella- chamber
Located between cells.
Intercloud gas
-clud rock, hill
khaos (Greek) gas, empty space
Low-density regions of the interstellar medium
that fill the space between interstellar clouds.
Intercostal
Latin
-costo- rib
or character of
Situated between the ribs.
Intercrystalline
Latin/Greek
-krystallinos- rock crystal
Between the crystals of a solid substance.
Interdependent
Latin
-depend- relying on
-ent causing an action, being in a specific state,
within
Mutually dependent; having a direct relationship
with one another.
Interferometer
Latin
-ferir- to strike
ing, to measure
An instrument for measuring very small lengths,
distances, and changes in the dimensions, den-
sity, and other properties of a substance by means
of the interferences of two rays of light.
Interlunar
Latin
inter- among, mutually, together, between
-luna- the moon
Pertaining to the period between the old and new
moon, during which the moon is not visible from
the earth.
Intermolecular
Latin
-moles- mass
-ule- small, tiny
Describes forces that are exerted by molecules on
each other and that, in general, affect the macro-
scopic properties of the material of which the
molecules are a part.

108 Internal
Internal
Latin
internus- within
or character of
Of, relating to, or located within the limits or sur-
face; inner.
Internode
Greek
-node the point on a plant where a leaf stalk or
petiole attaches to the stem
Distance along the stem of a plant between two
successive nodes.
Internuclear
Latin
-nucula- kernel, little nut
Located between nuclei.
Interphase
Greek
-phasis appearance
The stage of cell division during which the chro-
mosomes are uncondensed and are copied.
Interspecific
Greek
-specif- appearance/kind
Refers to a relationship occurring between species.
Interstellar
Latin
-stella star
Between or among the stars (“interstellar gases”).
Interstitial
Latin
-sistere to stand
Situated in the interstices or spaces between
structures such as cells, organs, or grains of sand.
Intertidal zone
Latin/Old English/Greek
inter- (Latin) among, mutually, together, between
-tid- (Old English) division of time
-alis (Latin) of, relating to, characterized by
zone (Greek) girdle, celestial zone
The marine zone located in the area of shoreline
between high and low tides.
Interval
Latin
-vallum ramparts
Space between objects.
Intestine
Latin
intestinus within, internal
The tubular portion of the alimentary canal extend-
ing from the stomach to the anus; in humans and
other mammals, the intestine consists of two seg-
ments, the small intestine and the large intestine.
Intracellular
Latin
intra- within, inside
-cellula- chamber
Occurring within a body cell or cells.
Intramolecular
Latin
-moles- mass
-ule- small, tiny
Pertains to the characteristics and properties of
any given molecule.
Intraspecific
Latin
-specif- appearance/kind
Referring to a relationship occurring within a
species.
Intrinsic
Latin
intrinsicus- inward
Relating to the central or core nature of a thing.
Intron
Latin
intron occurring within a gene
A segment of gene situated between exons that is
removed before the translation of messenger RNA.
Introvert
Latin
intr- inwardly, within
-vertere to turn
The anterior narrow portion that can be withdrawn
(introverted) into the trunk of a sipunculid worm.
Intrusive
Latin

Isopod 109
in- into, on, among
-trudere thrust
Referring to igneous rocks that form at depths
below the earth’s surface
Invertebrate
Latin
in- without
-vertebratus backbone
Having no vertebrae (backbone).
Inverted
Latin
in- to cause to be
-vertere to turn
Reversed in terms of the position, order, or condi-
tion of.
Ionic
Greek
ion- (ienai) to go, something that goes
Containing an atom or group of items that have
acquired a net electric charge.
Ionization
Greek
-zation action, process, or quality of
Energy required to remove most loosely held
electrons from an atom.
Ionosphere
Greek
The lower part of the thermosphere, where elec-
trically charged particles called ions are found.
Ipsilateral
Latin
ipse- self, same
-latus- side
or character of
Located on or affecting the same side of the body.
Iris
Latin
irid rainbow
In biology, the colored part of the eye that regulates
the amount of light allowed into the interior of the
eyeball; in botany, the name given to a group of
tropical flowering plants; in physics, a diaphragm.
Irrigate
Latin
in- to cause to be
-rigare to water
To supply dry land with water by means of
ditches, pipes, or streams; to water artificially.
Isobar
Greek
isos- equal, uniform, same, similar, alike
-baros weight, heavy; atmospheric pressure
Any of the lines on a map joining places that have
the same air pressure.
Isobaric
Greek
-baros- weight, heavy; atmospheric pressure
Of a thermodynamic process in which a sub-
stance experiences no change in pressure.
Isochoric
Greek
-choros- of or having to do with volume
Refers to a thermodynamic process in which a
substance experiences no change in volume.
Isoelectric
Greek
-elektron- charge, electricity, dealing with posi-
tive and negative charges
Having an equal number of electrons outside the
nucleus.
Isomer
Greek
-meros part, share
Any of two or more nuclei with the same mass
number and atomic number that have different
radioactive properties and can exist in any of sev-
eral energy states for a measurable period of time.
Isometric
Greek
-metr- measurement
Equal in dimension or measurement; in biology,
relating to the contraction of muscles against an
immovable resistant force, where the length of
the muscle fibers remains the same.
Isopod
Greek
-pod foot

110 Isotactic
Any of numerous crustaceans of the order Iso-
poda, characterized by a flattened body bearing
seven pairs of legs, and including the sow bugs
and gribbles.
Isotactic
Greek
-taktos ordered
Describes the orientation of the methyl groups on
a polypropylene chain in plastics, which in this
case is all on the same side.
Isotherm
Greek
In meteorology, a line drawn on a weather map
indicating points of equal temperature.
Isotonic
Greek
-ton- tension
Of equal tension; having the same concentration
of solute on both sides of a membrane.
Isotope
Greek
-topos place
One of two or more atoms having the same
atomic number but different mass numbers.
Isthmus
Greek
isthmos narrow neck
In biology, a narrow strip of tissue connecting two
parts or lobes of a gland or organ; in earth science,
a narrow strip of land connecting two larger sec-
tions of land.

Jaundice
Latin
galbinus yellowish
Yellow discoloration of the eyes, mucous mem-
branes, and skin caused by deposits of bile, usu-
ally as a result of a disease, such as hepatitis.
Jejunum
Latin
ieiunus fasting (referring to its always being
found empty when dissected)
The very large section of small intestine begin-
ning at the end of the duodenum and ending at the
beginning of the ileum.
Joule
Old English
Joule English physicist (James Prescott Joule)
who developed the first law of thermodynamics
A unit of electrical energy equal to 10 million
ergs or one newton-meter.
Jurassic
French
jurassique/jura- mountains
Of or belonging to the geologic time, rock series,
or sedimentary deposits of the second period of
the Mesozoic era, in which dinosaurs continued
to be the dominant land fauna and the earliest
birds appeared.
Juvenile
Latin
iuvenis- young
-ile changing
Not fully grown or developed; young.

Kalemia
Latin
kalium- potassium
-haima- blood
plurals
The presence of excessive amounts of potassium
in the blood.
Kame
Middle English
camb comb
A short ridge or mound of sand and gravel depos-
ited during the melting of glacial ice.
Karyapsis
Greek
kary- nut, walnut, kernel, nucleus
-haptien to fasten, join
The process of the fussion or union of nuclei in
conjugating cells.
Karyochrome
Greek
-chrome pigment
A nerve cell whose nucleus is deeply stainable
although its body is not.
Karyocyte
Greek
The term for any cell possessing a nucleus.
Karyogamic
Greek
-gam- husband or wife; to marry
Describes a process pertaining to or characterized
by the union of two nuclei.
Karyogamy
Greek
-gam- husband or wife; to marry
The fusion of two cell nuclei following plasmog-
amy during fertilization.
Karyogenesis
Greek
The growth and development of the nucleus of a
cell.
Karyokinesis
Greek
-kinetikos- to move; set in motion
A phenomenon involved in the division of the
nucleus, usually an early stage in the process of
cell division, or mitosis.
Karyoklasis
Greek
-klastos- break, break in pieces

Ketone 113
The breaking down of the cell nucleus or nuclear
membrane.
Karyolymph
Greek
-lympha clear water, water nymph
The liquid part of a cell nucleus, as contrasted
with the chromatin and linin.
Karyolysis
Greek
Form of necrobiosis in which the nucleus of a cell
swells and gradually loses its chromatin.
Karyomegaly
Greek
-megas- large, great, big, powerful
-ly like, likeness, resemblance
Abnormal enlargement of the nucleus of a cell,
not caused by polyploidy.
Karyometry
Greek
The measurement of a cell nucleus.
Karyomorphism
Greek
The shape of a cell nucleus.
Karyophage
Greek
-phagos (phagein) to eat, eating
A protozoan that is capable of phagocytic action
on the nucleus of the cell it infects.
Karyoplasm
Greek
The nucleoplasm or protoplasm of the nucleus of
a cell.
Karyoreticulum
Greek
-reticul- net or networklike
The fibrillar part of the karyoplasm as distin-
guished from the fluid part of karyolymph.
Karyorrhexis
Greek
-rhxis action or process of bursting
Rupture of the cell nucleus in which the chroma-
tin disintegrates into formless granules that are
extruded from the cell.
Karyotype
Greek
-typos impression, figure
Representation of individual chromosomes cut
out from a photograph and grouped together.
Karyozoic
Greek
-zoon- animal, animal like
Existing in or inhabiting the nuclei of cells, as
certain protozoa.
Katolysis
Greek
kato- below
The incomplete or intermediate conversion of
complex chemical bodies into simpler com-
pounds; applied especially to digestive processes.
Keel
Old Norse
kjolr ship
Anything with a shape or purpose similar to that
of a ship’s keel in supporting the whole frame, as
in the breastbone of birds.
Keratin
Greek
keras- horn
A scleroprotein found in epidermal tissues and
modified into hard structures such as horns, hair,
and nails.
Ketone
German (from Latin)
keton short for aketon or acetone (acetone is
derived from Latin acetum [vinegar])
Any of a class or organic compounds having a
carbonyl group linked to a carbon atom in each of
two hydrocarbon radicals.

114 Kilogram
Kilogram
Greek
khilioi- thousand
-gramma small weight
A metric unit for the measurement of mass.
Kiloliter
Greek
khilioi- thousand
-litra unit of weight or capacity
A metric unit for the measurement of weight or
capacity; usually associated with liquids.
Kilometer
Greek
khilioi- thousand
ing; to measure
A metric unit for the measurement of distance.
Kindling
Old Norse
kynda- cause or to give birth to
Substances such as wook chips, dried sticks, or
charcoal that are relatively easy to ignite.
Kinematics
Greek
kinemat- mechanics of movement
The branch of mechanics that studies the motion
of a body, or a system of bodies, with no consid-
eration given to the body’s mass or the forces act-
ing on it.
Kinetic
Greek
kinetikos- to move; set in motion
The kind of energy relating to or produced by
motion.
Kinetochore
Greek
kinetos- moving
-khoros place
Structure that forms on the centromere during
mitosis for binding microtubules.
Kinetosome
Greek
The self-duplicating granule at the base of the fla-
gellum or cilium; similar to the centriole; also
called basal body or blepharoplast.
Kingdom
Old English
cyning- principal, chief
-dom property, jurisdiction
In biology, the highest level in the hierarchy of the
taxonomical classification of living organisms.
Kyphosis
Latin
kuphos- humpbacked, bent over
Exaggerated thoracic curvature.

Label
Middle English
lap- to wrap, to fold
-elle diminutive
To infuse or treat a substance with a radioactive
isotope or a fluorescent dye so that its course of
activity can be traced through a series of reac-
tions; usually done in a living organism.
Labrum
Latin
labr- lip
A structure forming the roof of the mouth in insects.
Labyrinthodont
Greek
labyrinthos- labyrinth, inner ear, double-headed
axe, of Lydian origin
-odontos tooth
A group of Paleozoic amphibians containing the
temnospondyls and the anthracosaurs.
Labyrinthus
Greek
labyrinthos- labyrinth, inner ear, double-headed
axe, of Lydian origin
-us thing
The portion of the inner ear characterized by the
semicircular canals and involved with hearing
and balance.
Laccolith
Greek
lakkos- cistern
-lith rock, stone
A mass of igneous rock intruded between layers
of sedimentary rock, resulting in uplift.
Lactescence
Latin
lac- milk or lactic acid
-escence giving off light of the kind or type specified
A milky appearance; milkiness
Lactic
Latin
Of or pertaining to milk; procured from sour milk
or whey, as in lactic acid; lactic fermentation.
Lactose
Latin/Greek
A disaccharide found in the milk of all mammals;
a sugar found in milk that breaks down into glu-
cose and galactose, and creates lactic acid
through fermentation.
Lacuna
Latin
lacuna lagoon
A space or cavity in bone that is occupied by a
bone cell or a cartilage cell.
Lagomorph
Greek
lagos- hare
-morph shape, form, figure, or appearance
Gnawing, herbivorous mammals, including rab-
bits, hares, and pikas.

116 Lake
Lake
Latin
lacus lake
A large inland body of freshwater or salt water.
Lamella
Latin
lamin- thin plate or layer, neurophysis of a vertebra
-ella dimunitive
A thin layer of bony matrix material.
Laminectomy
Latin/Greek
lamin- thin plate or layer, neurophysis of a vertebra
Surgical removal of the posterior arch of a vertebra.
Laparonephrectomy
Greek
lapar- the soft part of the body between the ribs,
hip, and flank; the loin
-nephr- kidney
Removal of the kidney by an incision in the loin.
Laparosalpingo-oophorectomy
Greek
-salping- tube, trumpet
-oophor- ovary
Removal of the Fallopian tube and ovary through
an abdominal incision.
Laparotomy
Greek
The act of cutting through the abdominal wall
into the cavity of the abdomen.
Larvae
Latin
larva mask, specter
The intermediary stage of development in insects
and many other animals between the egg and
adult stages. Referred to as a larva because the
adult stage is hidden or masked.
Laryngitis
Greek
larunx- part of the respiratory system in the neck,
cartilage, muscular tube
Inflammation of the larynx, often with a tempo-
rary loss of voice.
Lateral
Latin
lateralis side
Of, relating to, or being situated at or on the side.
Latitude
Latin
latus- wide
-tudo condition, state, quality
The angular distance north or south of the earth’s
equator, measured in degrees along a meridian, as
on a map or globe.
Lattice
Germanic
latte lathe
A regular, periodic configuration of points, parti-
cles, or objects throughout an area or a space,
especially the arrangement of ions or molecules
in a crystalline solid.
Lava
Latin
labi to fall
Molten rock that reaches the surface of the earth
through a fissure of a volcano.
Leach
Late Middle English
leche to wet or to infuse
To dissolve out soluble parts from, by running
water or other liquid through slowly.
Leaf
Old English
leaf leaf
Typically green, flattened structure of a plant that
is attached to a stem. It serves as the primary struc-
ture for energy production via photosynthesis.
League
Latin
leuga a measure of distance
A unit of distance equal to 3.0 statute miles (4.8
kilometers).
Lepidoptera
Greek
lepidos- scale, flake
-ptera feather, wing
The order of insects that includes butterflies and
moths.
Lepidosaurs
Latin
lepidos- scale, flake
-sauros lizard

Lever 117
A lineage of diapsid reptiles that appeared in the
Permian period and includes the modern snakes,
lizards, amphisbaenids, and tuataras, as well as
the extinct ichthyosaurs.
Leprosy
Latin
lepra- flake, scale, scaly, scabby
A slowly progressive, chronic infectious disease
characterized by granulomatous or neurotrophic
lesions in the skin, mucous membranes, nerves,
bones, and viscera, with a broad spectrum of clin-
ical symptoms.
Leptocephalus
Greek
leptos- thin
-kephale- head
-us thing
Transparent, ribbonlike migratory larva of the
European or American eel.
Lepton
Greek
leptos- small or fine
-on a particle
Any of a family of elementary particles that par-
ticipate in a weak interaction, including the elec-
tron, the muon, and their associated neutrinos.
Lethal
Latin
letum death
Relating to or capable of causing death.
Leuco
Greek
leukos white, clear, or colorless
Of or designating a reduced, colorless form of a
dye that is fixed on a fiber and then reconstituted
into the dye by means of oxidizing agents.
Leucoplast
Greek
leukos- white, clear, or colorless
A colorless plastid in the cytoplasm of plant cells
around which starch collects.
Leukemia
Greek
-haima- blood
plurals
A form of cancer characterized by uncontrolled
production of abnormal white blood cells.
Leukoblast
Greek
An immature white blood cell; also called a pro-
leukocyte.
Leukocyte
Greek
-kutos (cyto) sac or bladder that contains fluid
White blood cell, of which there are several types,
each having a specific function in protecting the
body from invasion by foreign substances and
organisms.
Leukocytopenia
Greek
Aconditioninwhichthereisadecreaseinoraninsuf-
ficiency of white blood cells circulating in the body.
Leukocytosis
Greek
An increase in the number of white blood cells in
the circulating blood.
Leukopenia
Greek
A condition in which the number of white blood
cells circulating in the blood is abnormally low.
Leukosarcoma
Greek
-sarko- flesh, meat
A type of lymphoma characterized by large numbers
of abnormal lymphocyte precursors in the blood.
Levator
Latin
levare- to lift, raise
Any muscle that elevates a part of the body.
Lever
Latin
levis light
A simple machine consisting of a rigid bar pivot-
ing on a fixed point and used to transmit force, as

118 Levorotatory
in raising or moving a weight at one end of a
beam by pushing down on the other end.
Levorotatory
Latin
laevus- left or counterclockwise
-rota- wheel
Rotating to the left in a plane of polarized light.
Libration
Latin
libra- balance
A very slow oscillation, real or apparent, of a sat-
ellite as viewed from the larger celestial body
around which it rotates.
Lichen
Greek
leikhein to lick
A plantlike organism consisting of a symbiotic
relationship between algae and fungi; usually
found on rocks and other regions with minimal
sources of food or water.
Life
Old English
lif life
The term designating any physiologically active
organism; the capacity to carry on all life processes.
Ligament
Latin
ligare- to bind, tie
-ment causing an action, or being in a specific state
A strong, elastic connective tissue that crosses a
joint and prevents excessive movement that could
dislocate the joint.
Ligant
Latin
ligare to bind, tie
A charged or uncharged molecule that can bind to a
metalmoleculeorionandformalarge,complexion.
Ligroin
German
ligroin ligroin
Petroleum ether; a volatile, flammable liquid
mixture of hydrocarbons obtained by the frac-
tional distillation of petroleum; used as a solvent.
Limicole
Latin
limus- mud, slime
-cole inhabit
Living in mud; a group of shore bird such as the
sandpipers or plovers.
Limivorous
Latin
limus- mud, slime
-vorare eat, swallow
Feeding on mud for the organic matter it contains;
characteristic of certain amnelids,
Limnetic
Greek
limne- lake
Relating to of having the characteristic of living
in the deep waters of a lake or pond.
Lingual
Latin
lingua- tongue, language
or character of
Of or pertaining to the tongue or tonguelike organ.
Lipid
Greek/French
lipos- fat
Any group of organic compounds, including fats,
oils, waxes, sterols, and glycerides, that are insol-
uble in water but soluble in organic solvents.
Liposome
Greek
lipos- fat
Droplet of phospholipid molecules formed in a
liquid environment.
Liquefy
Latin
liquere- flow, fluid, wave; to be liquid
-fy (ficare) make, do, build, produce
To cause to become liquid, especially to melt (a
solid) by heating or to condense (a gas) by cooling.
Liquid
Latin
liquere- flow, fluid, wave; to be liquid
Matterthathasadistinctvolumebutnospecificshape.
Lithium
Greek
lithos- stone, rock
A silvery-colored soft metal with the atomic
number 3. It is used as a therapeutic for bipolar,
depressive disorders. It is also used as a heat
transfer medium and is found in various alloys,
ceramics, and glass.

Lordosis 119
Lithosphere
Greek
lithos- stone or rock
The solid outer layer of the earth, consisting of
the crust and upper mantle.
Lithotomy
Greek
The surgical removal of a stone from the urinary
tract.
Lithotripsy
Greek
-tripsy (tribein) to crush; massage, rub, rubbing,
friction, grind
Surgical crushing of stones, as in the bladder or
ureters.
Litmus
Middle Dutch
leken- to drip
-mosi moss
A blue coloring matter obtained from lichens,
used as an acid/base indicator. It turns red in an
acidic pH of 4.5 and turns blue in bases at pH 8.3.
Littoral
Latin
litoralis pertaining to the seashore
On the shore, coastal; a zone between high and
low tides.
Lobopodium
Greek
lobos- rounded projection, especially a rounded
projecting anatomical part
-podos- foot
Blunt, lobelike pseudopodium.
Lobotomy
French/Greek
lobos- rounded projection, especially a rounded
projecting anatomical part
Surgical incision into the frontal lobe of the brain
to sever one or more nerve tracts. This technique
was formerly used to treat certain mental disor-
ders but now is rarely performed.
Locomotion
Latin
locus- a place or location
movere- to move
The ability of an organism to move from one place
to another place.
Lodestone
Old English
lad- way
-stan stone, rock
Magnetite, a common ore that is a natural mag-
net. At one time it was used by sailors to navigate.
Loess
German
losch loose
A buff to gray windblown deposit of fine-grained
calcareous silt or clay.
Longitude
Latin
longus- long
-tude state or quality
Angular distance on the earth’s surface, measured
east or west from the prime meridian at Green-
wich, England, to the meridian passing through a
particular position; expressed in degrees (or
hours), minutes, and seconds.
Lophophile
Greek
lophos- crest
preference for
Thriving on hilltops; hilltop plants, plant commu-
nities existing on hilltops.
Lophophore
Greek
lophos- crest
-phoros bearing
Tentacle-bearing ridge or arm within which is an
extension of the coelomic cavity in lophophorate
animals (ectoprocts, brachiopods, and phoronids).
Lophophyte
Greek
lophos- crest
-phyte plant
Plants that thrive on hilltop or crest environments.
Lophotrichous
Greek
lopho- ridge, crest
-tricho- hair
Refers to having two or more flagella at one end
of a cell.
Lordosis
Latin
lordos- to bend backward

120 Lumbar
An abnormal, exaggerated curvature of the verte-
bral column in the lumbar region.
Lumbar
Latin
lumbus loin
Relating to the lower back or small of the back.
Lumen
Latin
lumen an opening, light
In biology, the space or cavity within an organ or
organ system, such as within blood vessels or the
alimentary canal. In physics, the amount of light
given out through a solid angle by a source of one
candela intensity, radiating equally in all directions.
Luminous
Latin
lumen- an opening, light
Describes an object or living thing that has the
capacity to emit light, or glow.
Lunar
Latin
luna- the moon
Of, involving, caused by, or affecting the moon.
Lunarscape
Latin
luna- the moon
-scapus scene, view
Landscape of rock similar to the surface of the
moon.
Lunation
Latin
luna- the moon
-ation act or process
The period between new moons: 29 days, 12
hours, and 44 minutes.
Luster
Latin
lustrare light, illuminate
Shining or being reflected by light.
Lymph
Latin
lympha clear water, water nymph
Fluid, derived from tissue fluid, that is carried in
lymphatic vessels.
Lymphatic
Greek
lympha- clear water, water nymph
Of or relating to lymph, a lymph vessel, or a
lymph node.
Lymphocyte
Greek/Latin
Specialized white blood cell that occurs in two
forms: T lymphocyte and B lymphocyte.
Lymphoma
Greek
-oma tumor
Any of various usually malignant tumors that arise
in the lymph nodes or in other lymphoid tissue.
Lysogenic
Greek
ly- (luein) to loosen, dissolve, dissolution, break
Capable of causing or undergoing lysis.
Lysosome
Greek
A cytoplasmic, membrane-bound particle con-
taining hydrolytic enzymes that function in intra-
cellular digestive processes.
Lysozyme
Greek
-zume fermenting, leaven
An enzyme occurring naturally in egg white,
human tears, saliva, and other body fluids and
capable of destroying the cell walls of certain
bacteria and thereby acting as a mild antiseptic.

Macradenous
Greek
makros- long, large, great
-aden- lymph gland(s)
Having large glands.
Macrencephaly
Greek
-enkephalos- in the head
Overgrowth of the brain.
Macrocardius
Greek
-us thing
A fetus with an extremely large heart.
Macroevolution
Latin
-evolvere to unfold
Evolutionary change on a grand scale, encom-
passing the origin of novel designs, evolutionary
trends, adaptive radiation, and mass extinction.
Macrogamete
Greek
-gamos marriage
The larger of the two gamete types in a heteroga-
metic organism, considered the female gamete.
Macroglobulin
Greek
-globu- globe
-in of or derived from a protein
An immunoglobulin of very high molecular
weight, usually above 900,000.
Macronucleus
Greek
-us thing
Large nucleus that controls the functions of the cell.
Macrophage
Greek
A large white blood cell that can engulf hundreds
of bacteria.
Macrovolt
Greek
-volt electric potential
Large electric potential (one million volts).
Madreporite
Latin
madre- mother
-pora- passageway
-ite component of a part of a body
A perforated. platelike structure in most echino-
derms that forms the intake for their water-
vascular systems.

122 Mafic
Mafic
Latin
ma- the element magnesium
Containing or relating to a group of dark-colored
minerals that are composed chiefly of magnesium
and iron in igneous rock.
Magma
Greek
mag- to knead
-ma form or character of
The name given to molten rock under the surface
of the earth. Magma becomes lava if it escapes
from a volcano to the earth’s surface.
Magnet
Greek
magnes stone from Magnesia (city in Asia
Minor)
An object that is surrounded by a magnetic field
and that has the property, either natural or
induced, of attracting iron or steel.
Magnetosphere
Greek
magnes- stone from Magnesia (city in Asia
Minor)
Region around an object where the influence of
the object’s magnetic field can be felt.
Magnification
Latin/Greek
magn- great
-fic- to make
The process of making things look larger.
Magnitude
Latin
magnu- large
-tude state, quality, condition of
The overall size of a quantity.
Malacoderm
Greek
malacia- softening of tissue
-derm skin
Having soft skin or soft flexible bodies, as is char-
acteristic of fireflies.
Malacopterygia
Greek
-pterug- wing
plurals
Order of fishes where the fins are soft and closely
jointed; carp is an example.
Malacosarcosis
Greek
-sarko- flesh, meat
Softness of muscular tissue.
Malacostracan
Greek
malako- soft
-ostracon shell
Any member of the crustacean subclass Malacos-
traca, which includes both aquatic and terrestrial
forms of crabs, lobsters, shrimps, pillbugs, sand
fleas, and others.
Malaria
Italian
mala- bad
-aria air
Air infected with a noxious substance capable of
causing disease.
Malignant
Latin
malignus bad, attach, malign
Relates to a disease that is threatening to life; vir-
ulent; cancerous.
Malleable
Latin
malleus- hammer
-able capable, be inclined to, tending to, given to
A property of metal enabling it to be pounded or
rolled into thin sheets.
Mallophaga
Greek
mallos- wool
Chewing lice; extensive group of small insects
that are parasitic in nature on birds and mammals
and feed on feathers and hair.
Malnutrition
Latin
mala- bad
-nutrire- to suckle, nourish
-entcausinganaction,beinginaspecificstate,within
Poor nutrition related to or caused by an insuffi-
cient or poorly balanced diet, faulty digestion, or
faulty use of foods.
Maltase
Greek
malt- seed or grain
-ase indicating an enzyme

Meatus 123
Enzyme in plants and animals that breaks down
disaccharide maltose into glucose.
Maltose
Greek
malt- seed or grain
Disaccharide sugar in which both monosaccha-
ride parts are glucose.
Mammal
Latin
mamma- breast
or character of
An animal with hair that feeds its young with
milk from mammary glands.
Mammary
Greek
mamma- breast
Of or relating to the breasts (e.g., mammary
glands).
Mandible
Latin
mandere to chew
The lower jaw of vertebrates.
Mantle
Latin
mantellum layer
In geology, the layer of earth between the central
molten core and the surface crust.
Manubrium
Latin
manus- hand
A bony segment of the sternum shaped like a
handle.
Marine
Latin
mare sea
Of or relating to the sea.
Marsupial
Greek
marsuppos- pouch or purse
Mammal that bears its immature young in a mar-
supium, or pouch.
Mass
Greek
maza mass, large, amount
The property of a body that is a measure of its
inertia; commonly taken as a measure of the
amount of material the body contains and that
causes it to have weight in a gravitational field.
Mastication
Greek
mastikhan- to grind the teeth
The process of using one’s teeth to chew and
grind food.
Mastoid (process)
Greek
mastos- breast
-oid (oeides) resembling; having the appearance of
A small process resembling a nipple that is found
on the temporal bone.
Matter
Latin
materia substance from which something is
made
Something that occupies space and can be per-
ceived by the senses; a physical substance or the
physical universe as a whole.
Maxilla
Latin
maxilla jawbone
The fusion of two bones in mammals forming the
upper jaw.
Maxilliped
Latin
maxilla- jawbone
-ped foot
One of the pairs of head appendages located just
posterior to the maxilla in crustaceans; a thoracic
appendage that has become incorporated into the
feeding mouthparts.
Maxima
Latin
maximus greatest
The greatest values assumed by a function over a
given interval.
Mean
Old English
maenan to tell of
The average of a group of sample numbers as cal-
culated by dividing the sum of the numbers by the
number of samples.
Meatus
Latin
meare to pass
An opening or a canal—for example, the external
auditory meatus.

124 Mechanical
Mechanical
Greek
mekhane- machine, device
or character of
Relating to a machine or the functionality of a
machine. Mechanical advantage refers to the
measurement of the output force of the machine
(lever) versus the input force.
Meconium
Greek
mekonion poppy juice
The first feces of the newborn; the coloration is
usually greenish black to light brown.
Median
Latin
medius middle
The average that gives the midpoint of a range or
distribution.
Medium
Latin
medius middle
An intervening substance through which some-
thing else is transmitted or carried.
Medulla
Latin
merulla middle
The inner core of certain structures or organs.
Medusa
Latin
medein to protect
Tentacled, bell-shaped, free-swimming body
plan of cnidarians.
Megalocephaly
Greek
megal- large, great
-kephalikos head
A birth defect that causes an abnormally large head.
Megaspore
Greek
megas- large, great, big, powerful
-spora seed
In plants, a haploid (n) spore that develops into a
female gametophyte.
Meiosis
Greek
meion- smaller, less
The cellular process that results in the number of
chromosomes in gamete-producing cells being
reduced to one-half, and that involves a reduction
division, in which one of each pair of homologous
chromosomes passes to each daughter cell, and a
mitotic division.
Melanin
Greek
melas- the color black, dark
Dark brown pigment of many animals, giving
brown and yellow coloration to skin and/or hair.
Melanocyte
Greek
An epidermal cell capable of synthesizing melanin.
Melanoderma
Greek
-derma skin
Black or dark skin coloring (pigmentation); liter-
ally, black skin.
Melanoma
Greek
-oma community
A dark-pigmented, usually malignant tumor aris-
ing from a melanocyte and occurring most com-
monly in the skin.
Membrane
Latin
membrana thin skin
Thin layer of tissue composed of epithelial cells
and connective tissue that covers a surface.
Meningitis
Greek
mening- meninx
Inflammation of the meninges of the brain and
the spinal cord, most often caused by a bacterial
or viral infection.
Meniscus
Greek
mensikos moon, month
The concave or convex upper surface of a nontur-
bulent liquid in a container.
Meridian
Latin
medius- middle
-die day
In astronomy, a great circle passing through the
two poles of the celestial sphere and the zenith of
a given observer.

Metalloid 125
Meristem
Greek
meristos- divided
-en to make or cause
The undifferentiated plant tissue from which new
cells are formed, as that at the tip of a stem or root.
Mesentery
Greek
mesos- middle
-enteron gut
A membrane that suspends many of the organs of
vertebrates inside fluid-filled body cavities.
Mesoderm
Greek
mesos- middle
-derma skin
The germ layer formed between the ectoderm and
the endoderm of an embryo.
Mesoglea
Greek
mesos- middle
-gloia glue
The clear, inert, jellylike substance that makes up
the majority of the bodies of jellyfish, comb jel-
lies, and certain other primitive sea creatures.
Mesomorphic
Greek
mesos- middle
Existing in a state of matter intermediate between
liquid and crystal; describes any individual having
the characteristics of a stout, healthy physique
developed from the embyronic mesomorphic layer.
Meson
Greek
mesos- middle
-on a particle
The class of elementary particles with masses
between baryons and leptons.
Mesophyll
Greek
mesos- middle
-phullon leaf
The ground tissue of a leaf, sandwiched between
the upper and lower epidermis and specialized for
photosynthesis.
Mesophyte
Greek
mesos- middle
-phyte plant
A plant that has adapted to grow in areas having
moderate moisture conditions.
Mesosphere
Greek
mesos- middle
The zone of the earth’s interior that extends from
the lithosphere to the core.
Mesozoic
Greek
mesos- middle
-zoikos- of animals
An era of geologic time between the Paleozoic
and the Cenozoic, occurring between 248 and 65
million years ago.
Metabolism
Greek
meta- between, after, beyond, later
The complex of physical and chemical processes
involved in the maintenance of life.
Metacarpus
Greek
-karpos- wrist
-us thing
The part of the human hand that includes the five
bones between the fingers and the wrist.
Metagalaxy
Greek
-galakt milk
The assemblage of all the galaxies.
Metal
Greek
metallon- mine, ore, quarry, any of a category of
Any member of the class of substances repre-
sented by gold, silver, copper, iron, and tin.
Metallic
Latin/Greek
Having characteristics of metals.
Metalloid
Latin/Greek

126 Metallurgy
A nonmetallic element, such as arsenic, that has
some of the chemical properties of a metal.
Metallurgy
Latin/Greek
-ourgos worker
The science and technology involving the study
of metals.
Metamere
Greek
-meros part
Condition of being made up of serially repeated
parts; serial segmentation.
Metamorphic
Latin/Greek
Refers to a change of physical form, structure, or
substance, especially rock that has changed from
its original form through the application of heat
and pressure.
Metamorphosis
Greek
A change in the form of an animal during normal
development after the embryonic stage.
Metaphase
Greek
-phaseis appearance
The stage of mitosis and meiosis where chromo-
somes align along the metaphase plate.
Metapopulation
Greek/Latin
-populus- the people
A population subdivided into several small and iso-
latedpopulationsasaresultofhabitatfragmentation.
Metatarsus
Greek
-tarsos- instep
-us thing
The middle part of the human foot that forms the
instep and includes the five bones between the
toes and the ankle.
Metatheria
Greek
-ther- wild animal
plurals
Infraclass of marsupial mammals.
Metathesis
Greek
-tithenai to transpose, to place
A chemical reaction in which a double decompo-
sition occurs, causing parts of two reacting struc-
tures to swap places.
Meteor
Greek
meteoron things in air
The luminous phenomenon observed when a
meteor enters the atmosphere.
Meteorite
Greek
meteoron- things in air
A metallic or mineral mass that has fallen to earth
from space.
Meteorologist
Latin/Greek
A person who is a specialist in the study of the
weather, the atmosphere, and forecasting.
Meteorology
Latin/Greek
bodies of knowledge
The study of earth’s atmosphere, weather, and
climate.
Meter
Greek
meter (metron) instrument or means of measur-
ing; to measure
A metric unit used in the measurement of length
equivalent to 39.37 inches.
Methanogens
Greek
methano- methane
Organisms that require anaerobic conditions and
that produce methane gas.

Microtubules 127
Methionine
Greek
meth- containing a methyl group
-thio- compound containing sulfur
A sulfur-containing amino acid.
Micaceous
Latin
mica- grain
Pertaining to or containing mica; a laminar rock
structure much like mica.
Micelle
Latin
mica- grain, crumb
-elle diminutive
A unit in colloids composed of complex mole-
cules that can alter size without chemical change.
Microbiologist
Greek
mikros- small
One who specializes in the science of microbiology.
Microbiophagy
Greek
mikros- small
-phagia eat, eating; consume, ingest
Destruction or lysis of microorganisms by a phage.
Microcephalic
Greek
mikros- small
Having a small head or a small cranial cavity.
Microfilaments
Greek/Latin
mikros- small
-filum- thread
Any of the minute fibers throughout the cyto-
plasm of a cell that function primarily in main-
taining its structural integrity.
Microfilaria
Greek
mikros- small
-filum- thread
plurals
The minute larval form of the slender, threadlike
filarial worm.
Micrometer
Greek
micro- denotes one-millionth of a part
to measure
One-millionth of a meter, symbol µm; used in
many types of microscopic science, such as cellu-
lar biology.
Microneme
Greek
mikros- small
-nema thread
One of the types of structures composing the apical
complex in the phylum Apicomplexa; these struc-
ture are slender and elongate, leading to the ante-
rior, and thought to function in host cell penetration.
Microorganism
Greek
mikros- small
-organ- complex structure; tool
A very small living thing.
Microprocessor
Greek/Latin
mikros- small
-processus- setting out, series of steps
An integrated circuit that contains the entire cen-
tral processing unit of a computer on a single chip.
Micropyle
Greek
mikros- small
-pyle gate
Small opening at one end of an embryo sac.
Microscope
Greek
mikros- small
-skopein to view, examine
An optical instrument that uses a lens or a combina-
tion of lenses to produce magnified images of small
objects.
Microspheres
Greek
mikros- small
-sphaera ball
Structures composed only of protein that have
many properties of a cell.
Microtubules
Greek/Latin
mikros- small
-tubus- pipe
-ule little, small

128 Microvilli
Small hollow cylinders about 25 nm in diameter
and 0.2–25 m in length.
Microvilli
Latin/Greek
mikros- small
-villus shaggy hair
Tiny hairlike folds in the plasma membrane that
extend from the surface of many absorptive or
secretory cells.
Microvolt
Greek
mikros- small
-volt electric potential
Small electric potential (one millionth of a volt).
Microwave
Greek/English
mikros- small
-waven undulating, wavy
Electromagnetic radiation of frequency 1010
–
1012
Hz.
Micturation
Latin
mictum- to make water
The act or process of urinating.
Migration
Latin
migrans- to roam, wander, change places
The process of moving from one place to
another.
Mimicry
Greek
mimikos- imitator or mimic
A method of camouflage used in nature by an
organism that involves the blending and conceal-
ment of one’s identity by the effective use of color
or shading.
Mineral
French
miniere- mine
or character of
A naturally occurring, homogeneous inorganic
solid substance having a definite chemical com-
position and characteristic crystalline structure,
color, and hardness.
Mimicry in Nature
The process of natural selection has cre-
ated some incredible relationships in
nature. Members of all species seek the
survival of their kind. Both prey and pred-
ator are subjected to environmental
stresses on their numbers that can limit
their growth and ultimately threaten their
survival. This is a constant. Their abilities
to adapt to changes, to modify their
behaviors, and to compete with others for
common resources such as food and water
are continuously challenged in nature.
But the amazing story is the process and
randomness of natural selection. This
selective process is not a willful or prede-
termined direction of genetic change, but
rather the result of chance mutations over
extended periods of time. It is the forces
of nature that choose certain sets of phe-
notypes and eliminate others.
Consider the use of mimicry as a
selective process. There are several vari-
eties of mimicry, and all of them capital-
ize on characteristics that have sustained
a population’s growth in a given area.
Batesian mimicry is the best known. This
strategy is defined by a model species
that possesses some sort of protective
feature, such as a stinger, spines, or a
toxin, and a species mimicking the model
that does not. Batesian mimicry is exem-
plified by the American coral snake and
the common milk or king snake. The
coral snake is a venomous species with a
very powerful poison, whereas the milk
snake or king snake is not at all venom-
ous. Yet the physical resemblance—the
phenotype—is so striking that predators,
including most humans, avoid the harm-
less snake. These snakes are marked with
alternating yellow, red, and black bands.
It is the arrangement of the bands that is
the giveaway. The saying “Red against
yellow: kill a fellow. Red against black:
friend to Jack” is well known among Boy
Scouts and outdoorsmen. There is little
doubt that Batesian mimicry has allowed
king snakes to flourish in the United
States.

Monoamine 129
Miocene
Greek
meion- less
-kainos recent
An epoch of the Upper Tertiary period, spanning
Miscible
Latin
miscere- to mix
-ible capable
Capable of undergoing mixing or blending.
Miticide
Latin
miti- mite
A type of pesticide that kills mites that live on
plants, livestock, and people.
Mitochondrion
Greek
mitos- warp thread
-khondro- granule, cartilage
Membranous organelle in which aerobic respira-
tion continues and produces ATP molecules.
Mitogen
Greek
mit(os)- a thread
Any substance or agent that stimulates mitotic
cell division.
Mitosis
Greek/Latin
mitos- warp thread
The process in cell division by which the nucleus
divides.
Mixture
Latin
miscere- to mix
-ure act, process, condition
The act of combining; any combination of materials
that can be separated by ordinary physical means.
Mode
Latin
modus manner
In statistics, the average representing the sample
value that occurs the most times; that which
occurs most frequently in a series of observations.
Model
Latin
modulus small measure
A simplified version of a physical system that
would be too complicated to analyze in full detail.
Molarity
German
mole- the amount of a substance containing
Avogadro’s number of units
-ar- relating to or resembling
The molar concentration of a solution.
Mole
German
molekulargewient molecular weight
Quantity of a substance that has a mass in grams
numerically equal to its formula mass.
Molecule
Latin
moles- mass
-ule little, small
The smallest particle of a substance that retains
all the properties of the substance and is com-
posed of one or more atoms.
Molluscicide
Latin
mollusca- soft-bodied and prominent shell
A type of pesticide that kills snails and slugs.
Mollusk
Latin
mollis- soft
molluscus thin-shelled
Phylum of animals having a soft, unsegmented
body.
Moment
Latin
movere to move
The product of a quantity and its perpendicular
distance from a reference point.
Momentum
Latin
movimentum to move
A measure of the motion of a body equal to the
product of its mass and velocity.
Monoacid
Latin
mono- one, single, alone
-acere to be sour
An acid having one replaceable hydrogen atom.
Monoamine
Middle English
-amine any of a group of organic compounds

130 Monobasic
derived from ammonia by the replacement of one
or more hydrogen atoms by a hydrocarbon radical
An amine compound containing one amino group.
Monobasic
Latin
-base- basis
Having only one hydrogen ion to donate to a base
in an acid-base reaction.
Monocotyledon
Greek
mono- one, alone, single
-kotuledon a kind of plant, a seed leaf, a hollow or
cup-shaped object
Any of a class or subclass (Liliopsida or Mono-
cotyledoneae) of chiefly herbaceous seed plants
having an embryo with a single cotyledon, usu-
ally parallel-veined leaves, and floral organs
arranged in cycles of three.
Monocular
Greek/Latin
-oculus eye
Of or pertaining to a single eye.
Monoecious
Greek
-oikos house
Having male and female sex organs on the same
organism.
Monogamy
Greek
-gamos marriage
The condition of having a single mate at any one
time.
Monohybrid
Greek
-hybrida mixed offspring
Pertaining to or describing an individual, organ-
ism, or strain that is heterozygous for the single
trait or gene locus under consideration.
Monohydrate
Middle English
-hydr- water
A crystalline compound that contains one mole-
cule of water.
Monolayer
Middle English
-lay- to place in or bring to a particular state or
position
A film or layer of a compound one molecule thick.
Monomer
Greek
-meros a part, division
Small, individual molecule that forms a polymer.
Mononucleosis
Latin
-nucula- little nut, nucleus
-osis abnormal condition
A disease marked by extreme fatigue, high fever,
and swollen lymph nodes, caused by an abnor-
mally large number of white blood cells with sin-
gle nuclei in the bloodstream.
Monothermia
Greek
plurals
A condition in which the temperature of the body
remains the same throughout the day.
Monothetic
Greek
-thetikos- fit for placing
Denotes a taxonomic group classified on the basis
of a single character, as opposed to polythetic.
Monotocous
Greek
-toco- childbirth, delivery, labor
Giving birth to but one offspring at a time.
Monotreme
Greek
-trema hole, perforation
The order of egg-laying (oviparous) mammals,
including the duck-billed platypus and spiny
anteater.

Monotropic 131
Monotrichous
Greek
-trich- hair
Having a single polar flagellum; said of a bacte-
rial cell.
Monotropic
Greek
stimulus
The Great Library of Alexandria
It can be said the Great Library of Alexandria
(Egypt) was the best-known and one of the fore-
most libraries of the ancient world. Build by King
Ptolemy II (309–246 BC) near where the temple of
Muses (i.e., museum, from the word musaeum)
once stood, this structure is now little more than a
ruinous sublevel. But imagine an edifice so large
that it contained an ornate main hall and ten great
halls, each with armaria (i.e., wooden chests) con-
taining thousands of handwritten papyrus scrolls
from all points of the known world. Every one of
the great halls was dedicated to a specific academic
discipline. Scholars met, taught, and studied in an
enlightened environment where knowledge and
learning flourished.
Following the conquest of Egypt by Alexander
the Great, the Greeks along with the Egyptians built
this library as a seat where quite possibly all knowl-
edge from the beginning of the world to the current
time was archived and used by many of the most
influential scientists, mathematicians, philoso-
phers and artists. This massive repository housed
the compositions of philosophers Aristotle and
Plato; the ancient Greek playwrights Sophocles and
Euripides; the father of medicine, Hippocrates; the
father of geometry, Euclid; and many other brilliant
men, such as the legendary astronomer Aristarchus
of Samos, who, in a missing manuscript, hypothe-
sized a heliocentric solar system—that is, with the
sun at the center and the planets, including earth,
revolving around it. The manuscripts of one of the
greatest mathematicians in history, Archimedes—
“On the Equilibrium of Planes,” explaining the
laws of levers, and “On Floating Bodies,” explain-
ing the law of equilibrium of fluids—were also
stored in the great library.
Men were sent to distant shores to copy manu-
scripts for the library. Ships were stopped at the
port of Alexandria and searched for written works
that could be borrowed and copied. The originals
were kept in the library and copies were returned
to the owners. We can only guess at how much sci-
entific and mathematical knowledge had to be
rediscovered because of the destruction of the
library.
Historians dispute the who and when of the
destruction of the Library of Alexandria. Julius
Caesar had the port of Alexandria burned ca. 48 BC
when he occupied the city. Scholars contend that
that was a significant, but not a fatal, blow to the
library. It is estimated that over 70,000 scrolls were
destroyed by Caesar that day. However, many thou-
sands of scrolls had been moved in anticipation of
Caesar’s conquest.
Some argue that Christian zealots in the fourth
century destroyed the manuscripts, but not the
library, because of the pagan teaching and learning
that took place within its walls. Others say that the
complete destruction of the library occurred at the
hands of Muslims under the command of the Caliph
Omar ca. AD 683, but this theory is discounted by
most.
An inscription dedicated to Tiberius Claudius
Babillus of Rome (d. AD 56) found at the Library of
Alexandria supports the existence of the library
after the time of Julius Caesar.

132 Monsoon
Affecting only one particular kind of bacterium,
virus, or tissue; a narrowing of attention where an
individual focuses on one entity.
Monsoon
Dutch (from Portugese)/Arabic
mawsim season
A wind system that influences large climatic
regions and reverses direction seasonally.
Morainic
French
morena- mound of earth
Oforrelatingtoanaccumulationofboulders,stones,
or other debris carried and deposited by a glacier.
Morphine
Latin
morph- shape, form, figure, or appearance
An opiate extract used in medicine to alleviate
severe pain.
Morphogen
Greek
A class of substances that is said to be present in
the embryo and that controls growth patterns.
Morphogenesis
Greek
Formation of the structure of an organism or part;
differentiation and growth of tissues and organs
during development.
Morphology
Greek
bodies of knowledge
The study of the physical structures of organisms,
in particular the soft tissues.
Mosaic
Greek
mouseion- shrine of the muses
An organism or part that is composed of two or
more genetically distinct tissues, owing to exper-
imental manipulation or to a faulty distribution of
genetic material during mitosis.
Motion
Latin
movere- to move
An act, process, or instance of changing position.
Mucus
Latin
mucus mucus
A protective lubricant consisting of mucin, water,
salts, and cells. This viscous fluid is secreted to pro-
tect cells, membranes, and various internal linings.
Multicellular
Latin
multus- much, many
-cella- chamber
Consisting of many cells.
Muscle
Latin
mus mouse
Contractile tissue used to propel, move, and pro-
tect the body.
Museum
Greek
mouseion shrine of muses
An edifice or institution where cultural, scientific,
historical, and contemporary artifacts, documents,
and exhibits are retained for study and enjoyment.
Mutation
Latin
mut- change, changeable
A relatively permanent change in hereditary
material, involving either a physical change in
chromosome relations or a biochemical change in
the codons that make up genes.
Mutualism
Latin
mutuus- borrowed or exchanged
Association between organisms of two different
species in which each member benefits.
Myalgia
Greek
myo- muscle
-algia pain, sense of pain; painful; hurting
Muscle pain.
Mycelium
Latin/Greek
myco- fungus
-helos- wart, nail, stud, corn
A mass of interwoven filamentous “threads” that
make up the vegetative part of a fungus.

Myotome 133
Mycology
Greek
myco- fungus
bodies of knowledge
The branch of botany that deals with fungi.
Mycorrhiza
Greek
myco- (mukes) fungi
-rhiza root
Mutualistic relationship between fungi and plants.
Myelin
Greek
myel- (muelos) bone marrow
A white fatty (lipid and lipoprotein) substance
that is found in the medulla of long bones and also
forms the insular layer of axons.
Myelodysplasia
Greek
-dys- painful, difficult, disordered, impaired,
defective, ill
-plasia (plassein) something molded; to mold
Abnormal or defective (poor or bad) formation of
the spinal cord.
Myocardium
Greek
myo- muscle
Specialized muscular tissue of the heart.
Myocyte
Greek
myo- muscle
Contractile cell (pinacocyte) in sponges.
Myofibril
Greek
myo- muscle
-fibrilla small fiber
Small part of a muscle fiber.
Myoglobin
Greek
myo- muscle
-globus- globular mass
Globular protein closely related to hemoglobin
and located in the vertebrate muscle.
Myomere
Greek
myo- muscle
-meros part
A muscle segment of successive segmental trunk
musculature.
Myometrium
Greek
myo- muscle
-metra- uterus
The smooth muscular layer lining the female uterus.
Myonecrosis
Greek
myo- muscle
-necro- death
Death of muscle tissue.
Myopia
Greek
muein- close to the eyes
-ops eye, optic
The condition of nearsightedness, where distant
objects appear blurred.
Myosin
Greek
myo- muscle
Protein made up of a chain of polypeptides that
forms filaments in smooth muscle fibrils.
Myotome
Greek
myo- muscle
A voluntary muscle segment in cephalochordates
and vertebrates; that part of a somite destined to
form muscles; the muscle group innervated by a
single spinal nerve.

Nadir
Arabic
nazara to watch or see
The point of the celestial sphere directly under
the observer; the opposite of zenith.
Naphtha
Greek
naphtha a flammable liquid issuing from the
earth
A class of several volatile and flammable liquid
mixtures of hydrocarbons that are distilled from
petroleum, coal tar, and/or natural gases.
Nasal
Latin
nas- nose
or character of
Of, in, or relating to the nose.
Nascent
Latin
nasc- born
-escent becoming
In the act of being formed, coming into existence,
forming.
Nasopharynx
Latin
nasus- nose
-pharunx throat
The part of the pharynx above the soft palate that
is continuous with the nasal passages.
Natural
Latin
natura- nature
or character of
Of or pertaining to nature; that which occurs by
chance or within the framework of natural design.
Nausea
Greek
nausie seasickness
A feeling of sickness in the stomach character-
ized by an urge to vomit.
Navel
Old English
nafela central point
The notch on the surface of the abdomen where
the umbilical cord is attached during gestation.
Nebula
Latin
nebula cloud or mist
A diffuse mass of interstellar dust or gas or both,
visible as luminous patches or areas of darkness
depending on the way the mass absorbs or
reflects incident radiation.
Necrobiosis
Greek
necro- death
The degeneration and death of the body’s cells
from natural processes.

Nephric 135
Necrocoenosis
Greek
necro- death
-koinos- shared
An assemblage of dead organisms
Necrophagia
Greek
necro- death
Feeding on the flesh of dead animals.
Nectobenthos
Greek
necto- swim
of the sea
Swimming off the seabed.
Nektonic
Greek
nekto- swimming
Describes numerous groups of marine and freshwa-
ter organisms capable of swimming against strong
currents;thesegroupsrangefromplanktontowhales.
Nematic
Greek
nemat- thread, that which is spun
Refers to liquid crystals that have molecules
arranged in loosely parallel lines.
Nematicide
Greek
A type of pesticide that kills nematodes (micro-
scopic wormlike organisms that live in soil and
cause damage to food crops).
Nematocyst
Greek
-cyst (kustis) sac or bladder that contains fluid
Barbed harpoon within a cnidocyte of a cnidarian
that is used to spear prey.
Nematoda
Greek
-oeid shape, form, resembling
An order of worms having long, round, and gen-
erally smooth bodies.
Neon
Greek
neon new
A rare element that is a colorless, odorless, inert
gas and that forms a very small part of the air.
Neoplasia
Greek
neos- new, recent
-plas- something made, molded, or formed
plurals
The transformation of a cell into a cancer cell.
Neoplasm
Greek
neos- new, recent
An abnormal growth of new tissue in plants or
animals; a tumor.
Neopterygian
Greek
neos- new, recent
-pteryx- fin
plurals
Any of a large group of bony fishes that includes
most modern species.
Neoteny
Greek
neos- new, recent
-teinein to extend
An evolutionary process by which an organism
produces a descendant that reaches sexual matu-
rity while retaining a morphology characteristic
of the pre-adult or larval stage of an ancestor.
Neotropical
Greek
neos- new, recent
-tropikos the tropics
Of, pertaining to, or designating a zoogeographi-
cal realm that includes Central and South Amer-
ica and the adjacent islands.
Nephelometer
Greek
nephele- cloud
to measure
An instrument that determines the concentration
of suspended matter in a liquid dispersion by
measuring the amount of light that is scattered by
the dispersion.
Nephric
Greek
nephros- kidney
Relating to or connected with a kidney.

136 Nephridium
Nephridium
Greek
nephros- kidney
-id state, condition; having, being, pertaining to
A tubular, glandular excretory organ characteris-
tic of various coelomate invertebrates.
Nephritis
Greek
nephros- kidney
A variety of diseases causing chronic or acute
inflammation of the kidneys.
Nephrolithotomy
Greek
nephros- kidney
-lithso- stone, rock
Incision made into the kidney for removal of stones.
Nephrology
Greek
nephros- kidney
bodies of knowledge
The science that deals with the kidneys, espe-
cially their functions or diseases.
Nephropexy
Greek
nephros- kidney
-pexy fixing of a specified part; attaching to, a
fastening
Surgical fixation of a floating or mobile kidney.
Nephrosis
Greek
nephros- kidney
A noninflammatory disease of the kidneys that
chiefly affects the function of the nephrons.
Nephrostome
Greek
nephros- kidney
-stoma mouth
Ciliated, funnel-shaped opening of a nephridium.
Neuralgia
Greek
neur- nerve, cord
nervus- sinew, tendon
Acute pain radiating along the course of one or
more nerves.
Neurilemma
Greek
neur- nerve, cord
-eilema veil, sheath
A very delicate sheathlike covering of a nerve fiber.
Neurilemmitis
Greek
neur- nerve, cord
-eilema- veil, sheath
Inflammation of the neurilemma.
Neurilemmoma
Greek
neur- nerve, cord
-oma tumor
Tumor of the peripheral nerve.
Neurilemmosarcoma
Greek
neur- nerve, cord
-sarko- flesh, meat
-oma tumor
A malignant neurilemma.
Neuroglia
Greek
neur- nerve, cord
-glia glue
Tissue supporting and filling the spaces between
the nerve cells of the central nervous system.
Neurology
Greek
neur- nerve, cord
bodies of knowledge
Branch of science that deals with the study of the
nervous system.
Neuromast
Greek
neur- nerve, cord
-mastos knoll, breast
Cluster of sense cells on or near the surface of a
fish or amphibian that is sensitive to vibratory
stimuli and to water current.

Nodule 137
Neuron
Greek/Latin
neur- nerve, cord
-on a particle
A cell in the nervous system that is specialized to
conduct nerve impulses, allowing different parts
of the body to communicate.
Neuropeptide
Greek
neur- nerve, cord
-peptos- digestion, able to digest
Any of various short-chain peptides found in
brain tissue, such as endorphins.
Neuropodium
Greek
neur- nerve, cord
-podos foot
Lobe of the parapodium nearer the ventral side in
polychaete annelids.
Neuroptera
Greek
neur- nerve, cord
Insect order for dobsonflies, ant lions, and lace-
wings, having four net-veined wings.
Neurotoxin
Greek
neur- nerve, cord
-tox- poison
A toxin that can damage nerve tissue.
Neurotransmitter
Greek/Latin
neur- nerve, cord
-trans- across
-mittere to send
Chemical substance released from the end of a neu-
ron during the propagation of a nerve impulse, in
ordertotransmitorpassasignaltoanothernervecell.
Neurotrophic
Greek
neur- nerve, cord
-trophos- (trophein) to nourish, food, nutrition;
development
Relating to the nutrition and metabolism of tis-
sues under the influence of nerves.
Neutral
Greek
neutr- neither one nor the other
or character of
In chemistry, a solution that is neither acidic nor
basic, having a pH of 7.0.
Neutralization
Greek
In chemistry, the process of combining an acid
and a base, thus canceling the properties of both
and producing a salt and water.
Neutron
Greek
-on a particle
An uncharged elementary particle that has a mass
nearly equal to that of the proton and is present in all
knownatomicnucleiexceptforthehydrogennucleus.
Neutrophil
Greek
preference for
An abundant type of granular white blood cell
that is highly destructive of microorganisms; it
can be stained readily by neutral dyes.
Niche
Middle French
nicher to nest
The ecological role of an organism in a commu-
nity, especially in regard to food consumption.
Nimbus
Latin
nimbus cloud
Low, gray rain clouds.
Nocturnal
Latin
nocturnes- night
or character of
Relating to, pertaining to, or occurring at night.
Nodule
Latin
nodus knot
-ulus small one
A small, knoblike outgrowth, such as those found
on the roots of many leguminous plants.

138 Nomenclature
Nomenclature
Latin
nom- (nemein) to dictate the laws of; knowledge;
usage; order
-calator servant, crier
A system of names used in an art or science; the
procedure of assigning names to kinds and groups
of organisms in a taxonomic classification.
Nondisjunction
Latin
non- not, lack of
-jungere to join
The failure of paired chromosomes to separate
during cell mitosis.
Nonideal
Greek
non- not, lack of
idea- a plan, scheme, notion, or method
or character of
Pertains to a gas described by an equation of state
of the form pV ϭ znRT, where z is the gas devia-
tion factor, which depends on pressure, tempera-
ture, and gas composition.
Nonpolar
Greek
non- not, lack of
-polos- either of two oppositely charged termi-
nals, axis, sky
Refers to a substance that does not ionize when
combined with water.
Nonvascular
Latin
non- not, lack of
-vasculum- vessel
Lacking a vascular system for the transport of
nutrients throughout a plant.
Nonvolatile
Latin
non- not, lack of
-volare- to fly
-ile changing, ability, suitable, tending to
Pertains to that which does not readily evaporate
at room temperature and pressure.
Noradrenaline
Latin
nor- anti or not
-ren- the kidneys
or character of
A hormone that acts directly on specific receptors
to stimulate the sympathetic nervous system.
Norepinephrine
Greek
nor- anti or not
-nephros- kidneys
An endogenous adrenal hormone and synthetic
adrenergic vasoconstrictor; this hormone con-
stricts blood vessels and raises blood pressure.
Normal
Latin
norma- carpenter’s square
or character of
A perpendicular, especially a perpendicular to a
line tangent, to a plane curve, to a plane tangent,
or to a space curve.
Notochord
Greek
noton- back
-khorde gut, string of a musical instrument
A flexible rodlike structure that forms the main
support of the body in the lowest chordates, such
as the lancelet; a primitive backbone.
Notopodium
Greek
noton- back
-podos- foot
Lobe of a parapodium nearest the dorsal side in
polychaete annelids.
Nucleic (acids)
Latin
nucula- kernel, little nut
A group of very large organic compounds impor-
tant to the synthesis of protein molecules within
cells. DNA and RNA are the two most widely
known nucleic acids.
Nucleolus
Latin
-lus thing
A small, typically round granular body composed
of protein and RNA, and found in the nucleus of a
cell. It is usually associated with a specific chro-
mosomal site and involved in ribosomal RNA
synthesis and in the formation of ribosomes.

Nucleotide 139
Nucleonics
Latin
The science that deals with the study of the
nucleus of atoms.
Nucleophile
Latin
preference for
A chemical compound or group that tends to
donate or share electrons.
Nucleoplasm
Latin/Greek
Protoplasm of a nucleus, as distinguished from
cytoplasm.
Nucleosome
Latin/Greek
Any one of the repeating nucleoprotein units
consisting of histones forming a complex with
DNA.
Nucleotide
Latin
-ide nonmetal radical
Chemical compounds consisting of a heterocy-
clic base combined with a sugar and one or more
phosphate groups to form the basic structural
units of DNA and RNA.
The Einstein-Szilard Letter
Months after the discovery of uranium fission in
1939, a Hungarian-born Jewish American physicist
named Leo Szilard grew very concerned about the
skepticism of American scientists that atomic
energy from fission could be used for much of any-
thing, let alone an atomic bomb. His fear was com-
pounded by the fact that he and others believed
Nazi Germany was working on a program to
develop atomic weaponry. His suspicions were
aroused by the discontinuation of uranium ore sales
from Nazi-occupied Czechoslovakia.
If he was to persuade the Americans to begin a
program of their own before it was too late, he had
to convince President Roosevelt himself. Szilard
sought the help of perhaps the best-known scien-
tist in the world, Albert Einstein. Szilard, like Ein-
stein, had fled Nazi Germany and come to
America.
Szilard drafted a letter and took it to Einstein,
who signed it and agreed to have it delivered to the
president. Einstein was a pacifist, but he knew that
if the Nazis had sole possession of such a weapon,
it would mean defeat for the Allies in the coming
war.
In the Einstein-Szilard letter, the scientists con-
tended
This new phenomenon would also lead to
the construction of bombs, and it is conceiv-
able—though much less certain—that extremely
powerful bombs of a new type may thus be
constructed. A single bomb of this type, car-
ried by boat and exploded in a port, might very
well destroy the whole port together with
some of the surrounding territory. However,
such bombs might very well prove to be too
heavy for transportation by air.
In the letter reprinted below, President
Roosevelt gives his response.
This newly appointed “Uranium Board” had a
limited scope of action and an extremely limited
budget. Little to no action was taken toward the
development of the atomic bomb until December 6,
1941, the day before the attack on Pearl Harbor by
the Japanese. It was then that a large-scale research
effort called the Manhattan Project began the pro-
cess ultimately leading to the development of the
atomic bomb dropped on Hiroshima, Japan, in
August 1945.
THE WHITE HOUSE
WASHINGTON
October 19, 1939
My dear Professor:
I want to thank you for your recent letter and the most interesting and important enclosure.
I found this data of such import that I have convened a Board consisting of the head of the
Bureau of Standards and a chosen representative of the Army and Navy to thoroughly
investigate the possibilities of your suggestion regarding the element of uranium.
I am glad to say that Dr. Sachs will cooperate and work with this Committee and I feel this is
the most practical and effective method of dealing with the subject.
Please accept my sincere thanks.
Dr. Albert Einstein,
Old Grove Road,
Nassau Point,
Poconic, Long Island,
New York

140 Nucleus
Nucleus
Latin
-us thing
In biology, a large, membrane-bound structure
within a living cell, containing the cell’s hereditary
material and controlling its metabolism, growth,
and reproduction. In chemistry, the positively
charged central portion of an atom that comprises
nearly all of the atomic mass and that consists of
protons and neutrons—except in hydrogen, which
consists of one proton only. In astronomy, the com-
pact central core of a galaxy, often containing pow-
erful radio, x-ray, and infrared sources.
Nutrient
Latin
nutrire- to suckle, nourish
A source of nourishment or food.
Nyctalopia
Greek
nukt- night
-alaos- blind
-opia sight, eye
Night blindness.
Nyctanthous
Greek
nukt- night
-anthous flower
Describes plants that bloom or flower in the
evening, such as jasmine.

Observation
Latin
ob- toward, against, before
-serv- to serve
Any use of the senses to gather information.
Obstetrics
Latin/Greek
-statos- standing, stay; make firm, fixed, balanced
The branch of medicine that deals with the care of
women during pregnancy, childbirth, and the
recuperative period following delivery.
Occipital
Latin
-caput- head
or character of
Of or pertaining to the back part of the skull; the
occipital bone.
Occlude
Latin
occludere up close
To absorb and retain gases or other substances.
Occult
Latin
occulere to cover over
In medicine, a substance detectable only by micro-
scopic examination.
Octahedron
Greek
octa- eight
-hedron face
A Platonic solid with eight faces.
Octet
Italian
oct- eight
-(du)et group
A set of eight valence electrons forming a stable
configuration.
Octomerous
Greek
oct- eight
-meros part
Having eight parts; specifically, eightfold symmetry.
Oculomotor
Latin
oculus- eye, sight
-movere move
Moving or tending to move the eyeball.
Odometer
Greek
hodos- journey, way
to measure
A mechanical or digital device used to record dis-
tance traveled.

142 Odonata
Odonata
Greek
odontas toothed
An order of medium-to-large insects with elon-
gated, slender abdomens; dragonflies and damsel-
flies. Dragonflies hold wings horizontally when at
rest, have thick bodies, and are active fliers. Dam-
selflies hold wings vertically when at rest, have
slender bodies, and are less agile in flight.
Odontoid
Greek
odontas- toothed
Resembling a tooth; the odontoid process of the
axis bone.
Oestrus
Greek
oistros having strong desire; anything that drives
one mad; frenzy
The period during which the sexual desire and
attractions of the female may be heightened, lead-
ing to copulation.
Olefin
French
oleum- oil
-fier form, cause to become
Any of a class of unsaturated open-chain hydro-
carbons having the general formula CnH2n.
Olein
Latin
oleum- oil
-in natural chemical compound
An oily, yellow liquid occurring in animal and
vegetable oil.
Olfaction
Latin
olfacere- smell
The process of smelling.
Oligocene
Greek
oligos- little, few
-kainos recent
An epoch of the Early Tertiary period, spanning
Oligochaeta
Greek
oligos- little, few
-chaite long hair
Any of a class of hermaphrodite terrestrial or
aquatic annelids (such as earthworms) that lack a
specialized head.
Oligoclase
Greek
oligos- little, few
-klastos- break, break in pieces
Any of a class of common rocks forming series of
triclinic feldspars.
Oligomer
Greek
oligos- little, few
-mer segment
A polymer that consists of two, three, or four
monomers.
Oligosaccharide
Greek
oligos- little or few
-sakkhar- sugar
A carbohydrate that consists of a relatively small
number of monosaccharides.
Olivine
Latin (from Greek)
oliva- (Latin) color olive green
elaia- (Greek) olive green
-ine made of, resembling
A mineral silicate of iron and magnesium found
in igneous and metamorphic rocks.
Ommatidium
Greek
omma- eye
-idium small
One of the optical units of the compound eye of
arthropods and mollusks.
Omnivore
Latin
omnis- all
-vorare to devour
An organism that consumes a variety of plant and
animal material.
Oncogene
Greek
onco- mass, bulk, swelling
A gene in which mutation induces neoplasia
(cancer).
Oncosphere
Greek
onkinos- a hook
-sphaira ball
Rounded larva that is common to all cestodes and
that bears hooks.

Opisthaptor 143
Ontogeny
Greek
onto- a being, individual; being, existence
-geny birth, descent, origin, creation, inception,
beginning; race, sort, kind, class
The course of development of an individual
organism. The history or science of the develop-
ment of the individual being; embryology.
Oocyst
Greek
oion- egg
Cyst that forms around a zyogote of malaria and
related organisms.
Oocyte
Greek
oion- egg
Stageintheformationofanovum,justprecedingthe
firstmeioticdivision(primaryoocyte)orjustfollow-
ing the first meiotic division (secondary oocyte).
Oogenesis
Greek
oion- egg
The formation, development, and maturation of an
ovum.
Ookinete
Greek
oion- egg
-kinein to move
The motile zygote of malaria organisms.
Oolemma
Greek
oion- egg
The plasma membrane of the oocyte.
Oology
Greek
oion- egg
bodies of knowledge
The branch of biology that deals with the study of
eggs.
Oophoritis
Greek
oophor- ovary, egg
Inflammation of an ovary.
Ooze
Middle English
wose muddy ground
Soft mud or slime.
Opacity
Latin
opacus- shady
The quality or state of being opaque.
Opaque
Latin
opacus shady
Impenetrable by light; neither transparent or
translucent.
Operator
Latin
operare- to work
A genetic unit that regulates the transcription of
structural genes in its operon.
Operculum
Latin
operire to cover
A lid or flap covering an aperture, such as the gill
covers in some fish.
Operon
Latin
oper- operator
-on heredity unit
A unit of genetic material that functions in a coor-
dinated manner by means of an operator, a pro-
moter, and one or more structural genes that are
transcribed together.
Ophthalmology
Greek
ophthalmos- eye; sight
bodies of knowledge
The branch of medicine that deals with the anat-
omy, functions, pathology, and treatment of the eye.
Ophthalmopathy
Greek
ophthalmos- eye; sight
-patheia disease; feeling, sensation, perception
The study of the diseases of the eye and associ-
ated tissue.
Opisthaptor
Greek
opistho- backward, behind, at the back, after,
posterior
-haptein- to fasten
The posterior attachment organ of a monogenetic
trematode.

144 Opisthognathous
Opisthognathous
Greek
opistho- backward, behind, at the back, after,
posterior
-gnathos jaw
With the head deflexed such that the mouthparts
are directed posteriorly, as in the insect order
Hemiptera.
Opsonin
Greek
opson- a relish
Type of antibody in blood serum that weakens
bacteria and other foreign cells so that the phago-
cytes can destroy them more easily.
Optic
Greek
optikos- visable
Referring to vision or the science of optics or lenses.
Orbital
Latin
orbita- orbit
or character of
Refers to the wave function of an electron in an
atom or molecule.
Organ
Greek
organon- organized structure; pertaining to a par-
ticular body part with a specific function(s); tool,
implement
The aggregation of various tissues into a specific
structure designed to carry out some biological
function within a multicellular organism.
Organelle
Greek/Latin
implement
-elle diminutive
Specialized part of a cell; literally, a small organ
that performs functions analogous to those of
organs of multicellular animals.
Organic
Greek
implement
Of or pertaining to compounds containing carbon.
Johannes Kepler
It had been well over 1500 years since
the first and perhaps only major para-
digm in science had swept the Western
world. Now the paradigm was about to
shift. A bold new group of thinkers had
emerged in Europe to challenge the
accepted theories and to lay the founda-
tion for a more progressive approach to
science (a newly coined word) and
experimentation. The scientific revolu-
tion was about to begin.
Johannes Kepler, born in Germany on
December 27, 1571, was one of the first
to question contemporary thinking. He
wrote, “Geometry existed before the
Creation. It is co-eternal with the mind of
God. . . . Geometry is God himself.”
Even as a child, Kepler was gifted and
outspoken. He studied religion, mathe-
matics, and philosophy at a Protestant
seminary school. In his relatively seques-
tered life, he pondered the relationship
between God and the natural world. He
looked for mathematical evidence of har-
mony between the eternal and the natu-
ral. One might even describe him as a
patron of Pythagoras. For a time he
believed in the Platonic solids as a frame-
work for the orbits of the planets.
The number of known planets in
Kepler’s time was six. To Kepler, the
nagging question was, why only six?
Why not more? He struggled with the
explanation of the distances between the
planets according to Copernicus. He
spent years trying to formulate a reason-
able explanation of the data on planetary
positions that he had obtained from
Tycho Brahe. He wanted to develop an
experimental approach to studying plan-
etary design, but he needed baseline data.
He brilliantly determined that by using
the sun and the orbital period of Mars, he
could produce data establishing that the
orbital path of Mars was not circular. To
Kepler, such disharmony was very unset-
tling, but he clearly demonstrated that
the order and perfection of the heavens,
as described by the Greeks, was more
myth than fact.

Orthoptera 145
Organism
Greek
implement
An individual living animal or plant able to carry
on life functions through mutually dependent
systems and organs.
Organogenesis
Greek/Latin
implement
The formation and development of the organs of
living things.
Organosol
Greek
implement
-ol chemical additive
A colloidal dispersion in which an organic disper-
sion medium is used.
Orientation
Latin
orient- to adjust
Change of position by organs, organelles, or
organisms in response to external stimulus.
Orifice
Latin
or- mouth
-ficium a making, doing
An opening to a cavity or to a body; mouth.
Ornithodelphia
Greek
ornis- bird
-delphys- womb
plurals
Infraclass of monotreme mammals.
Ornithology
Greek
ornis- bird
bodies of knowledge
The branch of zoology dealing with the scientific
study of birds and their structure, classification,
habits, songs, and flight.
Orogeny
Greek/French
oros- mountain
The formation of mountains through plate tectonics.
Oropharynx
Greek
or- mouth
-pharynx cavity leading from the mouth and
nasal passages to the larynx
The part of the pharynx that extends from the
mouth to the larynx.
Orpiment
Latin
aurum- gold or yellow
-pigmentum pigment
A bright yellow mineral, arsenic trisulfide, that is
used as a pigment.
Orthoclase
Greek
ortho- straight, true, correct, right
-klasis to break
A variety of feldspar, essentially potassium alu-
minum silicate, or KAlSi3O8, characterized by a
monoclinic crystalline structure and found in
igneous or granitic rock.
Orthogenesis
Greek
The idea that the evolutionary path of a lineage
can acquire a trend that carries it in a continuous
direction; directional selection.
Orthopedics
Greek
-paideia- child rearing
The branch of medicine that deals with the pre-
vention or correction of injuries or disorders of
the skeletal system and associated muscles,
joints, and ligaments.
Orthoptera
Greek
An order of mandibulate insects including grass-
hoppers, locusts, and cockroaches; insects with
greatly enlarged hind legs with forewings modi-
fied into a tegmen.

146 Oscillate
Oscillate
Latin
os- mouth
-cillum to swing
To vary between alternate extremes, usually
within a definable period of time.
Osculum
Latin
os- mouth
-culum diminutive, little
Excurrent opening in a sponge.
Osmiridium
English
osme- from the smell of osmium tetroxide
-irid- rainbow
A mineral that is a natural alloy of osmium and
iridium, with small inclusions of platinum, rhod-
ium, and other metals.
Osmium
Greek
osme- smell from the smell of osmium tetroxide
A hard metallic element found in small amounts
in osmiridium and platinum ores.
Osmosis
Greek
osmos- thrust, push
Diffusion of fluid through a semipermeable
membrane from a solution with a low solute con-
centration to a solution with a higher solute con-
centration, until there is an equal concentration of
fluid on both sides of the membrane.
Osmotic
Greek
osmos- thrust, push
Relating to the diffusion of a fluid through a
semipermeable member until there is equal con-
centration on both sides of the membrane.
Osmotroph
Greek
osmos- thrust, push
-trophos (trophein) to nourish, food, nutrition;
development
A heterotrophic organism that absorbs dissolved
nutrients.
Ossification
Latin
oss- bone
-ify- (ficus) make, or cause to become
The natural process of forming bone from soft tis-
sue, including cartilage and membranous tissue.
Osteichthyes
Greek
osteon- bone
-ichthus fish
A class of fish having a skeleton composed of
bone in addition to cartilage.
Osteoarthropathy
Greek
osteon- bone
-arthr- joint
-patheia disease, feeling, sensation, perception
A disorder affecting bones and joints.
Osteoblast
Greek
osteon- bone
Cells that help create bone by facilitating the
deposit of minerals.
Osteoclast
Greek
osteon- bone
A large, multinucleate cell found in growing bone
that reabsorbs bony tissue, as in the formation of
canals and cavities.
Osteocyte
Greek
osteon- bone
A cell embedded in a bone.
Osteology
Greek
osteon- bone
bodies of knowledge
Part of anatomy dealing with the study of the
structure, development, and function of bones.
Osteopathy
Greek
osteon- bone
Disease involving the bones.
Osteoporosis
Greek
osteon- bone
-poros- a passage
A disease in which the bones become porous.

Oviger 147
Ostium
Latin
os- mouth
Name given to any small opening in an organism;
mouthlike opening in organisms; one of the small
porelike openings in sponges.
Otodynia
Greek
ot- ear; relationship to the ear
-dynia pain
Pain in the ear; earache.
Otolith
Greek
ot- ear; relationship to the ear
-lithos stone, rock
Calcerous concretions in the membranous laby-
rinth of the inner ear of lower vertebrates or in the
auditory organ of certain vertebrates.
Outcrop
Old English
ut- away from the center or middle
-crop to appear on the surface
A portion of bedrock or other stratum protruding
through the soil level.
Ovary
Latin
ovum- egg
The ovule-bearing lower part of a pistil that rip-
ens into a fruit.
Ovicide
Latin
ovum-egg
A type of pesticide that controls insect eggs
through the application of low-sulfur petroleum
oils to plants and animals.
Oviger
Greek
ovum- egg
-gerere to bear
Leg that carries eggs in pycnogonids.
Antoine Lavoisier
Antoine Lavoisier is considered by many to be the
father of modern chemistry. That title, however,
was not enough to save him from the guillotine in
1794. He was born in Paris, France, on August 26,
1743, to a family of wealth and privilege. Lavoisier
never endeared himself to the public. He worked
for a time as a tax collector in Paris. Clearly, he was
in the wrong profession at the wrong time. Nothing
he did scientifically could make up for the aristo-
cratic persona Lavoisier projected in the earlier
years of his life. Thus, when he made his final
appeal to the judge in the French court, the judge’s
response was simply “the Revolution has no need
of scientists.” He was taken out and executed along
with many others, including his father-in-law, who
was executed right before him.
Antoine Lavoisier was a remarkable chemist. He
was one of the first to quantify chemistry, that is, to
assign numbers to chemicals and to chemical reac-
tions. The law of conservation of matter was a direct
result of Lavoisier’s experiments. By carefully
weighing both reactants and products, he demon-
strated that the mass of the end products of a chem-
ical reaction is equal to the mass of the reactants.
Prior to the work of Lavoisier, there had only
been discussion of the possibility of the existence of
compounds. By his clever quantification of chemical
reactions, Lavoisier was able to prove that elements
do, in fact, combine to form compounds. Lavoisier
was the first to prove that water was a compound
composed of the elements hydrogen and oxygen. He
also demonstrated that the ratio of hydrogen to oxy-
gen is 2 to 1. Lavoisier’s Elementary Treatise of
Chemistry, published in 1789, was considered by
many to be the first chemistry textbook. It encapsu-
lated in an integrated perspective a modern approach
to chemistry and chemical analysis. In addition to
creating a chemical nomenclature and discounting
previously accepted chemical theories, such as the
phlogiston theory of matter, he introduced in his
writings a significant group of chemicals that could
not be broken down further. Those chemicals are
many of the elements we are familiar with today.
All this and more could not save him. His country
was in turmoil, and the French Revolution turned
even more violent in its latter stages. When Lavoisier
was arrested and brought to court, no one stood in his
defense. His peers and closest friends, who knew he
was innocent of the serious charges brought against
him, did nothing and said nothing. Everyone feared
for their own lives. The terror that was the French
Revolution struck such fear in the hearts of men that
they allowed the innocent to go down with the guilty.
A very short year and a half later, the French
government exonerated Lavoisier of all guilt. Too
little and far too late.

148 Ovine
Ovine
Latin
ov- sheep
Refers to sheep.
Ovipositor
Latin
ovum- egg
-pos- to place
Organ of female insects through which eggs are laid.
Ovoviviparity
Latin
ovum- egg
-vivi- life, alive
-parity to bring forth, to bear, producing viable
offspring, giving birth to
Retention of the developing fertilized egg within
the mother; a form of viviparity in which there is
no nutrition of hatched young.
Ovulation
Latin
ovum- egg
The process of releasing the ovum from the ovary.
Ovule
Latin
ovum- egg
-ule little, small
A minute structure in seed plants that develops
into a seed after fertilization.
Ovum
Latin
ov- egg
Plural ova; female gamete before fertilization.
Oxalate
French/Latin
oxal- a derivative of oxalic acid, found in plants
-ate meaning the salt or ester of the root acid
C2O4, the ion of oxalic acid Na2C2O4, salt of
oxalic acid.
Oxidation
French
oxide- a binary compound of an element or a rad-
ical with oxygen
Areactioninwhichtheatomsinanelementloseelec-
trons and the valence of the element is correspond-
ingly increased (originally, this was considered to
be the combination of a substance with oxygen).
Oxygen
Latin/Greek
oxus- acid, sharp
Anonmetallicelementconstituting21%oftheatmo-
sphere by volume that occurs as a diatomic gas, O2,
and in many compounds such as water and iron ore.

Palate
Greek/Latin
pal- flat
In mammals, the roof of the mouth. The bony
front part is the hard palate, and the muscular rear
part is the soft palate.
Paleoanthropology
Greek
palaois- ancient, old
-anthropo- human
bodies of knowledge
The study of fossils belonging to the genus Homo
(e.g., Homo erectus).
Paleocene
Greek/Latin
-recens recent
The earliest epoch of the Tertiary period, spanning
the time between 65 and 55.5 million years ago.
Paleontology
Greek
-ontos- having existed
bodies of knowledge
The study of the forms of life existing in prehis-
toric or geologic times, as represented by the fos-
sils of plants, animals, and other organisms.
Paleozoic
Greek
-zoikos- of animals
The second oldest division of geologic time; an
era of geologic time from the end of the Precam-
brian to the beginning of the Mesozoic.
Palpitate
Latin
palpare- to feel
To beat rapidly, as the heart.
Pandemic
Greek
pan- all
-demos- the people
An epidemic over a large region.
Paracentesis
Greek
para- beyond
-cente- puncture
The process of aspirating a cavity.
Paradox
Greek
para- beyond
-doxa explanation
A seemingly contradictory statement that may
nonetheless be true.

150 Paraffin
Paraffin
Latin
parum- little, not very
-affinis associated with
A member of the alkane series.
Parallax
Greek
para- beside; near; alongside
-allos other
The apparent change in the position of an object
resulting from the change in the direction or posi-
tion from which it is viewed.
Parallel
Greek
-allos one another
Extending in the same direction; everywhere equi-
distant and not meeting.
Paralysis
Greek
-luein- to release
The loss of either sensation or movement or both
on a part of the body, usually as a result of injury.
Paramagnetic
Greek
-magnes- stone from Magnesia (city in Asia Minor)
Relating to or being a substance in which an
induced magnetic field is parallel and propor-
tional to the magnetizing field, but is much
weaker than in ferromagnetic materials.
Paramecium
Greek
-mekos- length
Freshwater species of the genus Paramecium that
is typically long and narrow, with an oral groove
on the side.
Parasite
Greek
-sitos- grain, food
-ite resident
An organism that grows, feeds, and is sheltered
on or in a different organism while contributing
nothing to the survival of its host.
Parasitism
Greek
-sitos- grain, food
The condition of an organism living in or on another
organismatwhoseexpensetheparasiteismaintained.
Parasitology
Greek
-sitos- grain, food
bodies of knowledge
A branch of science that deals with parasites and
parasitism.
Parathyroid
Greek
-thureos- oblong shield; door
Four small kidney-shaped glands located later-
ally and posteriorly to the thyroid glands in the
neck; they secrete the parathyroid hormone.
Parenchyma
Greek
-enchyma infusion
Least specialized of all plant cell or tissue types.
Parietal
Latin
pariet- wall
or character of
In biology, refers to either the parietal bone of the
skull or the forming of a wall of a body part or
organ.
Parity
Latin
par- equal
An intrinsic symmetry property of subatomic par-
ticles that is characterized by the behavior of the
wave function of such particles under reflection
through the origin of spatial coordinates.
Parotid
Greek
par- by the side of, beside; associated, near
Pertaining to the salivary glands located on the
side of the head near the ears.
Parotitis
Greek

Penicillin 151
par- by the side of, beside; associated, near
-itis inflammation
Inflammation of the parotid glands, as in mumps.
Parsec (Parallax- second)
Greek
-allos- other
-sec (secundus) second
A distance at which an object will have a parallax
of one second of arc; 3.258 light years or 1.918 Þ
1023 miles.
Parthenogenesis
Greek
parthenos- virgin
A form of reproduction in which an unfertilized egg
develops into a new individual, occurring com-
monly among insects and certain other arthropods.
Particle
Latin
particula part
Any of the basic units of matter and energy.
Pathogenic
Greek
pathos- suffering, disease
Refers to an agent, typically a microbe that causes
disease or suffering.
Pathology
Greek
bodies of knowledge
The science of disease formation, processes,
causes, and effects.
Pediatrics
Greek
paideia- child rearing
-iasthai to heal
The branch of medicine that deals with the care
of infants and children and the treatment of their
diseases.
Pedigree
French
ped- foot
-de grue of crane (resembling a crane’s foot)
A diagram that traces a trait through several fam-
ily generations.
Pedipalp
Latin
ped- foot
-palp, -palpi, -palpo to touch, stroke
Oneofthesecondpairofappendagesnearthemouth
ofaspiderorotherarachnidthataremodifiedforvar-
ious reproductive, predatory, or sensory functions.
Peduncle
Latin
ped- foot
-uncle little
A primary flower stalk, supporting either a clus-
ter or a solitary flower.
Pelagic
Greek
pelagikos- (pelagos) sea
Of, relating to, or living in open oceans or seas rather
than in waters adjacent to land or in inland waters.
Pellicle
Latin
pellicula husk
Thin, protective membrane in some protozoa.
Pelvis
Latin
pelvis basin
A basin-shaped cavity at the base of the axial
skeleton formed by the fusion of six bones, the
ileum, pubis, and the ischium.
Penetrometer
Latin
penetr- inner or inside
ing; to measure
An instrument designed to measure the density,
compactness, and penetrability of a substance.
Penguin
Old Welsh
pen- white
-gwyn head
Any of various erect, short-legged, flightless
aquatic birds (family Spheniscidae) of the South-
ern Hemisphere.
Penicillin
Latin
penicillus- brush
Any of a group of broad-spectrum antibiotic drugs
obtained from penicillium molds or produced syn-
thetically; most active against gram-positive bac-
teria and used in the treatment of various
infections and diseases.

152 Pentahedron
Pentahedron
Greek
penta- five
-hedron face
A three-dimensional solid having five (plane) faces.
Pentamer
Greek
penta- five
-meros a part
A polymer consisting of five molecules.
Penumbra
Latin
paene- almost
-umbra shadow
The outer, almost darkened part of a shadow cast
during an eclipse that lies between the completely
darkened area and the fully lit area.
Peptide
English
pept(one)- digested
Any of various natural compounds containing
two or more amino acids linked by the carboxyl
group of one amino acid and the amino group of
another.
Peptize
Greek
pept(one)- digested
To change a gel into a colloid solution form.
Percolate
Latin
per- through, across
-co- together, with
-late bear, carry
To cause a liquid to pass through spaces of a
porous material.
Perennial
Latin
-annus- year
or character of
Refers to that which lasts year after year; a peren-
nial plant.
Pericardia
Greek
peri- around, about, enclosing
plurals
Thin, membranous, fluid-secreting sac in the area
around the heart.
Pericarditis
Greek
Inflammation of the tissue surrounding the heart.
Pericycle
Greek
-kyklos circle, wheel, cycle
Thin tissue layer found in vascular plants; can
produce lateral roots.
Peridotite
French
peridot- a yellowish green variety of olivine used
as a gem
Any of a group of igneous rocks composed
mainly of olivine and various pyroxenes and hav-
ing a granitelike texture.
Perigee
French (from Greek)
-ge earth, world
The point nearest the earth’s center in the orbit of
a moon or satellite.
Perihelion
Greek
-helios- sun
The point along an orbit of a planet at which the
planet is closest to the sun.
Perimorph
Greek
A mineral that encloses a different mineral.
Perineum
Greek
-inan to excrete
In females, the area between the anus and the vagina.
Period
Greek
-hodos journey, way
The geological length of time.

Phagocytosis 153
Periodic
Greek
-hodos- journey, way
Having or marked by repeated cycles.
Perissodactyla
Greek
perissos- odd
-dactylos toe
Order of odd-toed mammals (horses, zebras).
Peristalsis
Greek
-stellein- to place
Muscular contractions of esophagus.
Peritoneum
Greek
-teinein to stretch
The membrane that lines the walls of the abdom-
inal cavity.
Peritrichous
Greek
-tricho- made of hair
Pertains to having flagella all over a cell.
Permafrost
Latin/Middle English
permanere- to endure
-frost freeze; frozen
Permanently frozen subsoil continuous through-
out the polar region.
Permeable
Latin
per- through
-meare- to glide
Capable of being penetrated by liquids or gases.
Peroxide
Latin
per- large or largest portion of an element
-oxy(s)- sharp, acid
An oxide of an element or a radical that contains
the greatest possible amount of oxygen, especially
when there are oxygen atoms joined to each other.
Peroxisome
Latin/Greek
per- large or largest portion of an element
-oxy(s)- sharp, acid
A cell organelle containing enzymes such as cat-
alase and oxidase that catalyze the production
and breakdown of hydrogen peroxide.
Pesticide
Latin
pesti- plague, contagion
A chemical agent used to destroy pests.
Petal
Greek
petalon leaf
One of the often brightly colored parts of a flower
immediately surrounding the reproductive organs.
Petrochemical
Greek
petros- a rock, fossil, or stone
-chemeia- alchemy
or character of
A chemical derived from fossil fuels.
Petroleum
Latin
-oleum oil
Oily, flammable liquid that occurs naturally in
deposits, usually beneath the surface of the earth.
Petrology
Greek
bodies of knowledge
Branch of geology that deals with the study of
rocks, their mineral compositions, their textures,
and their origins.
Phagocyte
Greek
phagos- (phagein) to eat, eating
White blood cells that destroy pathogens by sur-
rounding and engulfing them.
Phagocytosis
Greek
The process by which a cell absorbs or eats waste
materials.

154 Phanerozoic
Phanerozoic
Greek
phainein- visible
-zoion living being
The most recent past geologic eon that includes
the Cenozoic, Mesozoic, and Paleozoic eras.
Pharmacology
Greek
pharmac- drug, medicine, or poison
bodies of knowledge
The study of the properties of drugs and their
effects on the body.
Pharyngotomy
Greek
pharyng- throat
An operation in which an incision is made into
the pharynx to remove a tumor.
Pharynx
Greek
pharyng- throat
Passage between the esophagus and the cavities
of the nose and mouth.
Phenocryst
Greek
phaino- showing, displaying
-krustallos ice, crystal, freeze, icelike
A conspicuous, usually large, crystal that is
embedded in porphyritic igneous rock.
Phenol
Greek
phen- related to or derived from benzene
-ol chemical derivative
A caustic, poisonous, white crystalline com-
pound derived from benzene and used in resins,
plastics, and pharmaceuticals, as well as in dilute
form as a disinfectant and antiseptic.
Phenology
Greek
phainein- to show, appear, display; making evi-
dent; literally, “to come”
bodies of knowledge
The seasonal life history of an insect population.
Phenomenon
Greek
phainomenon to appear
An observable event.
Phenotype
Greek
phainein-toshow,appear,display;makingevident;
literally, “to come”
-typos mark
The complete observable characteristics of an
organism or group including anatomic, physio-
logic, biochemical, and behavioral traits as deter-
mined by the interaction of genetic makeup and
environmental factors.
Pheromone
Greek
pherein- to carry, bear, support; go
-(hor)mone to rouse, or set in motion
A chemical secreted by an animal, especially an
insect, that influences the behavior or develop-
ment of others of the same species and often func-
tions as an attractant of the opposite sex.
Philodendrist
Greek
philos- love, fondness for, loving
-dendron- tree
One who has a special fondness for trees.
Phlebitis
Greek
phleb- blood vessel, vein
The inflammation of a vein.
Phlebosclerosis
Greek
phleb- blood vessel, vein
-skleros- hard
Thickening or hardening of the walls of the veins.
Phloem
Greek
phloios bark
The food-conducting tissue of vascular plants.
Phosphorus
Greek
phos- light
-pherein to carry, bear, support; go
A highly reactive, poisonous, nonmetallic ele-
ment found in safety matches and pyrotechnics.
Photochemical
Latin
photos- light, radiant energy
-alchymia- action of chemicals
or character of

Physical 155
Refers to chemicals and other pollutants reacting
in the presence of sunlight.
Photoelectric
Greek
-elector- beaming sun
-ic relating to or having some characteristic of
Pertains to the ejection of an electron from a sur-
face exposed to light.
Photometry
Greek
-metria (metron) the process of measuring; to
measure
The branch of science that deals with the mea-
surement of light output.
Photon
Greek
-on a particle
The smallest physical particle; it has no mass and
no charge, and is electromagnetic energy.
Photopsin
Greek
-opsis- sight, appearance
-in neutral chemical. protein derivative
The photoreceptor pigments found in the cone
cells of the retina that are the basis of color
vision.
Photoreceptor
Greek
-recept- receiver
A group of nerve cells that are sensitive to light
energy.
Photosensitive
Greek
-sensus- senses
Refers to something that is easily irritated by
light.
Photosphere
Greek
The intensely bright gaseous outer layer of a star,
especially of the sun.
Photosynthesis
Greek
-synthe- formation by combination
The process by which carbon dioxide is con-
verted into organic matter in the presence of the
chlorophyll in plants and under the influence of
light.
Phototropism
Greek
stimulus
Adjustment in the direction and rate of plant
growth in response to light.
Phycoerythrin
Greek
phukos- seaweed
-erythros red
A red phycobilin occurring especially in the cells
of red algae.
Phyllotaxy
Greek
phullon- leaf
-taxi arrangement, order
The manner in which leaves are arranged with
regard to the axis.
Phylogeny
Greek
phulon- race, class, tribe
-genes to give birth, kind, produce
Development and history of a species or higher
taxonomic grouping of organisms.
Phylum
Greek
phulon- race, class, tribe
The chief category of taxonomic classifications,
between kingdom and class, into which organ-
isms of common descent that share a fundamental
pattern of organization are grouped.
Physical
Greek
physica- physics
or character of
In physics, a term used to refer to or identify
material things. In biology, a term used to refer to
or denote the body as opposed to the mind or
spirit.

156 Physics
Physics
Greek
phusis- nature
The science of matter and energy and of the inter-
actions between the two, grouped into traditional
fields such as acoustics, optics, mechanics, ther-
modynamics, and electromagnetism, as well as
modern extensions including atomic and nuclear
physics, cryogenics, solid-state physics, particle
physics, and plasma physics.
Physiology
Greek
physio- form, origin
bodies of knowledge
The branch of biology dealing with the structure
and functions of living organisms and their parts.
Phytobenthos
Greek
phuton- plant
of the sea
The aquatic flora of the region at or near the bot-
tom of the sea.
Phytochrome
Greek
phuton- plant
-chrome pigment
A substance that produces a color in plant tissue.
Phytoplankton
Greek
phuton- plant
-planktos wandering
Minute, free-floating aquatic plants.
Pigment
Latin
pingere to paint
A coloring matter in animals and plants, espe-
cially in a cell or tissue.
Pineal
French
pomme de pin pinecone
An endocrine gland found in the middle of the
brain; it secretes melatonin and is named for its
pinecone shape.
Pinniped
Latin
pinnas- feather, wing
-ped foot
Ernest Rutherford
Ernest Rutherford is considered by many to be the
father of nuclear physics. He was born Earnest
Rutherford, the first Baron Rutherford of Nelson,
in New Zealand on August 30, 1871. He died on
August 19, 1937.
Rutherford became known for developing an
experimental design demonstrating the scattering
of nuclear (alpha) particles using gold foil. For a
time, he studied at the University of Cambridge in
England, where, during his investigations of wireless
wave energy and radioactivity, he coined the terms
alpha, beta, and gamma rays.
Rutherford moved to Canada and took a profes-
sorship in and chaired the Department of Physics at
McGill University. There he developed an explana-
tion for the constant rate of disintegration of radioac-
tive atoms, ultimately leading to the term half-life.
He went on to associate this process of atomic
decay with a precise, clocklike action. By examin-
ing the half-life of radium and knowing that radium
ultimately came from the degradation of uranium,
Rutherford was able to speculate about the age of
the earth. He placed the age at hundreds of millions
of years—not exactly accurate or narrow in its
scope, but it was a starting point that was picked up
by scientists later on. For this work, he was
awarded a Nobel Prize in Chemistry in 1908.
Rutherford began to feel left out of mainstream
science at McGill, so he moved to Great Britain and
was given the chair of the Department of Physics at
the University of Manchester. Here he ultimately
discovered the nature of the nuclei of atoms. He
theorized about “neutrons” in the nuclei as being
particles capable of countering the effects of posi-
tively charged protons and thus preventing the
nucleus from breaking apart.
His pioneering work in nuclear physics was instru-
mental in the establishment of the Manhattan Project.
During his work in nuclear science, Rutherford was
quoted as saying, “The energy produced by breaking
down the atom is a very poor kind of thing. Anyone
who expects a source of power from the transforma-
tions of these atoms is talking moonshine.”
He desperately wanted to avoid the development
of nuclear energy for use in weaponry until all the
nations of the world were at peace. Rutherford died
in 1937, well before the destructive power of
atomic energy was unleashed in 1945.

Pleistocene 157
Any of a suborder (Pinnipedia) of aquatic carniv-
orous mammals (such as a seal or walrus) with all
four limbs modified into flippers.
Pinocytosis
Greek
pinein- to drink
Introduction of fluids into a cell.
Pistil
Latin
pestle club-shaped
The female reproductive organ of a flowering
plant; it contains the stigma, style, and ovary.
Pitch
Anglo Norman
piche pitch
The auditory effect of sound frequency; the sap
that gathers from evergreen trees; any of the resin-
ous materials from the bitumens, such as asphalt.
Pituitary
Greek
pituitarius- of phlegm
ptuo- to spit
A small oval endocrine gland attached to the base
of the vertebrate brain, the secretions of which
control the other endocrine glands and influence
growth, metabolism, and maturation.
Placenta
Greek
plakoenta flat land, surface
A flat, membranous, highly vascular organ that
develops in the female mammal during preg-
nancy; it supplies nutrients and removes wastes
from the developing fetus.
Planet
Greek
planasthai to wonder
A heavenly body seeming to have a motion of its
own among the fixed stars.
Plankton
Greek
planktos wandering
The passively floating or weakly swimming, usu-
ally minute animal and plant life in a body of water.
Plasma
Greek
plastos (plassein) something molded (to mold)
Straw-colored fluid part of the lymph and blood
composed of water, electrolytes, proteins, glu-
cose, fats, and gases. Essential for carrying cellu-
lar elements of the blood and maintaining acid-
base balance.
Plasmalemma
Greek
plastos- (plassein) something molded (to mold)
The thin membrane immediately surrounding the
cytoplasm of a cell that restricts the passage of
molecules into the cell.
Plasmodesmata
Greek
plastos- (plassein) something molded; to mold
-desma bond, adhesion
A strand of cytoplasm that passes through an
opening in the cell walls and connects the proto-
plasts of adjacent living plant cells.
Plasmolysis
Greek
plastos- (plassein) something molded (to mold)
Contraction of a cell caused by loss of water.
Platyhelminthes
Greek
platus- flat
-helminth worm
Any of various parasitic and nonparasitic worms
of the phylum Platyhelminthes, such as a tape-
worm or a planarian, characteristically having a
soft, flat, bilaterally symmetrical body and no
body cavity.
Platypus
Latin
platus- flat
-pous foot
A flat-tailed, semiaquatic mammal, resembling a
duck and having webbed feet and a snout; egg
laying.
Pleiades
Greek
peleiades flock of doves
The cluster of seven stars also known as the Seven
Sisters, located in the constellation Taurus the
Bull.
Pleistocene
Greek
pleistos- most
-kainos recent, new
An epoch of the Quaternary period, between 1.8
million years ago and the beginning of the
Holocene epoch.

158 Pleomorphic
Pleomorphic
Greek
ple- many, more
Refers to the occurrence of two or more structural
forms during a lifespan.
Pleura
Greek
pleura rib, side
Thin membrane that covers a lung and lines the
chest cavity in mammals.
Plexus
Greek
plectere to plait, braid
In biology, a network-like structure formed by
nerves, blood vessels, or lymphatic vessels.
Pliocene
Greek
pleion- more
-kainos recent, new
Final epoch of the Tertiary period, spanning the
time between 5.3 and 1.8 million years ago.
Plutonic
Greek
pluto- the god of the lower world in classical
mythology
Refers to intrusive rocks that form under the
earth’s surface.
Pneumonia
Greek
pneumon- lung, breath
plurals
An acute or chronic disease marked by inflamma-
tion of the lungs; caused by viruses, bacteria, or
other microorganisms and sometimes by physical
and chemical irritants.
Pneumonocentesis
Greek
-kentesis- pricking
Surgical perforation or puncture of a lung to
remove fluid, pus, or blood.
Poikilotherm
Greek
poik- varied
-thermos combining form of “hot” (heat)
An animal that can fluctuate its temperature.
Polar
Greek
polos either of two oppositely charged terminals;
axis, sky
Relating to or characterized by a dipole.
Polarity
Greek
polos- either of two oppositely charged terminals;
axis, sky
Intrinsic polar orientation; having two opposite
attributes.
Polarization
Greek
polos- either of two oppositely charged terminals,
axis, sky
-ar- relating to or resembling
-ize- to cause
The partial or complete polar separation of posi-
tive and negative charges in a nuclear, atomic, or
chemical system.
Pollen
Latin
pollen fine flour
Tiny, grainlike structures containing the sperm
cells of an angiosperm; they are produced by the
anthers of flowers.
Pollination
Latin
pollen- fine flour
The transfer of pollen to the female cone in coni-
fers or to the stigma in angiosperms.
Polyatomic
Latin
poly- many or much
-atomos- indivisible
Consisting of many atoms.
Polycythemia
Latin/Greek
poly- many or much
-haima blood
A condition marked by an abnormally large num-
ber of red blood cells in the circulatory system.
Polygenic
Greek
poly- many or much

Polythetic 159
Of or relating to more than one gene.
Polyhalophilic
Greek
poly- many or much
-hal- salt
preference for
Describes marine organisms that thrive in a wide
range of salinities.
Polyhedron
Greek
poly- many or much
-hedron head
A three-dimensional, symmetrical shape made up
of many faces.
Polyhybrid
Greek
poly- many or much
-hybrida offspring of mixed parents
In genetics, the offspring of parents differing in
more than three specific gene pairs.
Polymer
Greek
poly- many or much
-meros a part
A large molecule assembled from small, individ-
ual molecules.
Polymerase
Greek
poly- many or much
-meros- parts
-ase enzyme
An enzyme used to convert two or more mole-
cules into a polymer.
Polymorphism
Greek
poly- many or much
The ability to appear in more than one form.
Polymyalgia
Greek
poly- many or much
-myo- muscle
Pain affecting several muscles.
Polyp
Greek
poly- many or much
-pous foot
A hydra or coral, having a cylindrical body with a
single opening; a nonmalignant tumor or growth
extending from the mucosa into the lumen of an
organ, such as in the large intestine.
Polypathia
Greek
poly- many or much
-pathos- suffering from
plurals
The presence of several diseases at once.
Polyploidy
Greek
poly- many or much
-ploid- having a number of chromosomes that has
a specified relationship to the basic number of
chromosomes
Having one or more extra sets of chromosomes.
Polyprotic
Greek
poly- many or much
-pro-,prot-before,forward;for,infavorof;infrontof
Of or relating to an acid that can donate more than
one proton to a base, or relating to a base that can
accept more than one proton.
Polysyndactyl
Greek
poly- many or much
Having two or more instances in the same indi-
vidual of side-to-side fusion of digits.
Polytene
Greek
poly- many or much
-tainia ribbon, tapeworm
Relating to or having large multistranded chro-
mosomes whose corresponding chromomeres are
in contact.
Polythetic
Greek
poly- many or much
-thetos- placed
Pertains to a category or class that is defined in
terms of a broad set of criteria that are neither nec-
essary nor sufficient. Each member of the category
must possess a certain minimal number of defining
characteristics, but none of the features must nec-
essarily be found in each member of the category.

160 Polyuria
Polyuria
Greek
poly- many or much
-urea urine
Excessive excretion of urine because of a disease
such as diabetes.
Pons
Latin
pons bridge
A bundle of nervous tissue located on the ventral
surface of the spinal cord at the base of the brain;
it connects the medulla oblongata to higher
regions in the brain.
Population
Latin
populus- the people
A group of organisms of the same species living
in the same area at the same time.
Porcine
Latin
porc- pig or hog
Of or consisting of swine; related to or resem-
bling swine (pigs and hogs).
Porifera
Latin
porus- pore
-ferre to bear
A pore-bearing organism.
Positron
Greek
posi- positive charge
-tron a particle
The particle having the same mass and spin as an
electron but having a +1 charge caused by the
interaction of cosmic rays with matter.
Posterior
Latin
post- after, behind
Located behind a part or toward the rear of a
structure.
Potential
Latin
poten- power, strength, ability
Describes the energy that an object possesses but
has not yet used because of its position or condition.
Pound
Latin
pondo by weight
A unit of weight equal to 16 ounces.
Power
Latin
potis able, powerful
The amount of energy consumed per unit of time.
Precession
Latin
prae- earlier, before, prior to
-cedere- to go
The term used to denote a globe spinning on its axis
and describing the wobble as the globe slows down.
Precipitate
Latin
-capit- to throw headlong, the head
To cause a solid substance to be separated from a
solution.
Precipitation
Latin
-capit- to throw headlong, the head
Water droplets or ice particles condensed from
atmospheric water vapor.
Precocial
Latin
-coquere- to cook, ripen
or character of
Refers to a chick that leaves the nest immediately
after hatching.
Predator
Latin
praedari- to prey upon
-or condition or activity
A predatory person, animal, or thing thing that
preys upon, devours, or destroys another.
Prehensile
Latin
prehensus to clasp or seize
Refers to appendages that are adapted for clasp-
ing or grasping.
Prenatal
Latin
-nasci be born

Prokaryotic 161
or character of
Existing or occurring before birth.
Pressure
Latin
premere- to exert steady weight or force against;
bear down on
-ura act; process; condition
Force applied uniformly over a surface, measured
as force per unit of area.
Prey
Latin
praeda booty, prey
An animal taken by a predator as food.
Primary
Medieval Latin
primus- leader
In geology, the term used to describe the charac-
teristics of any rock at the time of its formation.
In chemistry, relating to the replacement of one
or more atoms by other atoms in a chemical
reaction.
Primate
Medieval Latin
primus- leader
A member of the order of mammals that includes
monkeys, apes, and humans.
Prism
Greek
prizein to saw off
A piece of glass that is usually cut into a triangu-
lar shape so that light can travel through, and so
that the colors of the visible light are separated.
Probability
Latin
pro- before; forward; for, in front of; in place of
-abilis- to do something, specific action
The chance that a given event will occur; a logi-
cal relation between statements such that evi-
dence confirming one confirms the other to some
degree.
Probiotics
Latin/Greek
Beneficial bacteria used to ease digestive ailments.
Proboscidea
Greek
-boskein to feed
Mammalian order that includes elephants.
Prodromal
Greek
-dromos- race course, running
or character of
Refers to the time following incubation period
when the first signs of illness appear.
Producer
Latin
-duct- lead, take, bring
An organism that has the capacity to make its own
food either by photosynthesis or by chemosynthesis.
Product
Latin
-duct lead, take, bring
That which results from the operation of a cause;
a consequence, effect.
Prognathous
Greek
-gnathos jaw
Having the head horizontal and the mouthparts
directed anteriorly.
Prognosis
Greek
-gnos- know, learn, discern
A prediction of the probable course and outcome
of a disease.
Program
Greek
-gramma something written or drawn; a record
Data instructions fed into a computer to control
the actions of the computer.
Prokaryotic
Greek
-karyon- kernel, nucleus
Lacking a membrane-bound nucleus and mem-
branous organelles, as in bacteria and archaea.

162 Prominence
Prominence
Greek/Latin
-minere- to jut or threaten
The incredibly huge masses of gases that burst
forth from the chromosphere of the sun.
Pronotum
Greek
-noton- the back
The upper, often shieldlike, hardened body-wall
plate located just behind the head of an insect.
Propagation
Latin
-pangere- to fasten
-ate- of or having to do with
The multiplication or natural increase in a popu-
lation; the dissemination of something to a larger
area or greater number.
Propellent
Latin
-pellere- to drive
-ant a person who, the thing which
The fuel and oxidizer of a rocket that provides the
thrust needed for the rocket to escape earth’s gravity.
Prophase
Greek
-phainein to show
The stage of cell division in which the chromo-
somes condense and become visible.
Prosencephalon
Greek
The anterior portion of the forebrain, including
the frontal lobe and the olfactory bulbs.
Prosimians
Latin
-simia- ape, monkey
Of or belonging to Prosimii, a suborder of primates
that includes the lemurs, lorises, and tarsiers.
Prostate
Greek
-histanai to set, place
A gland that wraps around the urethra in males. It
is responsible for releasing urine from the urinary
bladder to the exterior, and it produces seminal
fluid, a principal component of semen.
Protactinium
English
pro-,prot-before,forward;for,infavorof;infrontof
-actinium element actinium
A rare, extremely toxic radioactive element, which
decays into actinium.
Protandrous
Greek
-andr- man, male, men, masculine
-us thing
Of or relating to a flower in which the anthers
release their pollen before the stigma of the same
flower is receptive.
Protection
Latin
-tegere- to cover, ward off, guard, defend
The act of safeguarding, preserving, or shielding.
Protective
Latin
-tegere- to cover, ward off, guard, defend
Describes the act of guarding another person from
danger or injury and providing a safe environment.
Protein
French
proteine of the first quality
Any group of complex organic macromolecules
containing carbon, hydrogen, oxygen, nitrogen,
and usually sulfur. Proteins are composed of one
or more chains of amino acids and include many
substances, such as enzymes, hormones, and anti-
bodies, that are necessary for the proper function-
ing of an organism.
Proteolysis
Greek
prote- protein
A reaction sequence of the noncyclic pathway of
photosynthesis,triggeredbyphotonenergy,inwhich
water is split into oxygen, hydrogen, and electrons.

Pseudopodia 163
Proterozoic
Greek
proteros- earlier
-zoikos- of animals
-ic (ikos) relating to or having ome characteristic of
Relating to the geologic era characterized by the
first signs of single-celled organisms, plant algae.
Protist
Latin
protos- first formed, original, earliest
-ist performs an action
UnicellularorganismbelongingtokingdomProtista.
Protium
Greek
-ium chemical element
The most abundant isotope of hydrogen, with
atomic mass of 1.
Protocell
Greek/Latin
-cella chamber
A structure that has a lipid protein membrane and
carries on energy metabolism it existed before the
first true cell.
Protogynous
Greek
-gune woman, women, female
Referring to animals that are sequential hermaph-
rodites, where that animal is first biologically
female, having only female sexual organs, and
then changes to become biologically male.
Protolithic
Greek
-lith- rock, stone
Of, relating to, or characteristic of the very begin-
ning of the Stone Age; Eolithic.
Proton
Greek
-on a particle
An elementary particle that is identical to the
nucleus of the hydrogen atom, that along with
neutrons is a constituent of all other atomic
nuclei, that carries a positive charge numerically
equal to the charge of an electron, and that has a
mass of 1.673 Þ 10–27
kg.
Protoplast
Greek
-plastos (plassein) something molded (to mold)
Plant cell from which the cell wall has been
removed.
Protostome
Greek
-stoma mouth
An animal whose mouth develops from or near
the blastopore; an opening in the early embryo.
Prototheria
Greek
-theria wild animal, monotremes
Subclass of Cretaceous and early Cenozoic mam-
mals; extinct except for egg-laying monotremes.
Prototype
Greek
-tupos impression
An original type, form, or instance serving as a
basis or standard for later stages.
Protozoa
Greek
-zoan animal, living being; life
Single-celled microorganisms of the sub-kingdom
Protozoa; lowest form of animal life.
Proximity
Latin
proximus- nearest, next
The state, quality, sense, or fact of being near or
next to; closeness.
Pseudocoelom
Greek
pseudes- false
-koiloma cavity
Body cavity lying between the digestive tract and
body wall.
Pseudopodia
Greek
pseudes- false
-podion base, foot
A fingerlike projection on the body of an amoeba
used for movement.

164 Psychokinesis
Psychokinesis
Greek
psych- mind, consciousness, mental process
-kinetikos- to move; set in motion
The production or control of motion by a subject
without any intermediate physical energy.
Psychosomatic
Greek
-soma- (somatiko) body
Oforrelatingtoadisorderhavingphysicalsymptoms
but originating from mental or emotional causes.
Psychrometer
Greek
psychros- cold
to measure
Instrument that measures humidity.
Pterodactyl
Greek
pteron- feather, wing
Small, typically tail-less winged reptile existing
in the Jurassic and Cretaceous periods.
Pterygoid
Greek
pterug- wing
Relating to the region of the sphenoid bone of the
skull; winglike muscle.
Pulmonary
Latin
pulmo- lung
Relating to or involving the lung.
Pulsar
Latin
pullere- to beat
A relatively small star composed of neutrons that
emit radiant energy in regular pulses.
Pupil
Latin
pupilla little doll; pupil of the eye (named for the
tiny reflections on the eye)
The hole in the center of the iris that light travels
through in order to be focused on the retina.
Purine
Latin
purus- clean
The nitrogenous bases, adenine and guanine,
found in DNA.
Putrefaction
Latin
putrefacere- to make rotten
The process of creating a strong, foul odor by
emitting gases from the decomposition of organic
material.
Pylorus
Latin
pule- gate
-ouros guard
The lower section of the stomach that includes the
passageway into the duodenum of the small intestine.
Pyrimidine
Latin
pur- fire
-ide- group of related chemicals
The nitrogenous bases, cytosine and thymine,
found in DNA.
Pyroclastic
Greek
pur- fire
-klastos broken
Composed chiefly of rock fragments of volcanic
origin.
Pyroxenes
Greek
pur- fire
-xenos stranger
Any of a group of crystalline silicate minerals
common in igneous and metamorphic rocks and
containing two metallic oxides.
Pyrrole
Greek
pyre- red
-ole a heterocyclic chemical with a five-mem-
bered ring
A five-membered heterocyclic ring compound,
C4H5N, that has an odor similar to chloroform
and is the parent compound of hemoglobin.
Pyuria
Greek
puo- pus
-uria urine
Pus found in the urine; usually an indication of an
infection.

Quadriceps
Latin
quadi- four
-caput head
A very large muscle on the anterior surface of the
thigh; it contains four heads (cusps).
Quadruped
Latin
quadi- four
-ped foot
A four-footed animal that uses all four feet for
walking and running.
Quantum
Latin
quantus how great
The smallest amount of a physical quantity that
can exist independently, especially a discrete
quantity of electromagnetic radiation.
Quartz
German
quarz mineral quartz
A very hard mineral composed of silica.
Quasar
English
quasi- having a likeness to something
-(stell)ar star
A starlike object that has a large red shift and
emits powerful blue light and often radio waves.
Quaternary
Latin
quartern- four
ThesecondperiodoftheCenozoicera,spanningthe
time between 1.8 million years ago and the present.
Quiescence
Latin
quies- still, quiet
A state in which a seed or other plant will not ger-
minate or grow until the requisite environmental
conditions occur.
Quintessence
Latin
quinta- fifth
-essentia essence
The fifth or last and highest essence in ancient
and medieval philosophy, above fire, air, water,
and earth, that permeates all nature and is the sub-
stance composing the heavenly bodies.

Rabies
Latin
rabere to rave
A fatal disease caused by a virus that is transmit-
ted by a mammal; the symptoms include hydro-
phobia, convulsions, heightened excitability, and
muscular spasms in the throat.
Radial
Latin
ray- spoke of a wheel
Of or characterized as being arranged in a raylike
fashion.
Radiant
Latin
radiare to radiate
Of or referring to energy traveling by means of
electromagnetic waves.
Radioactivity
English
radi- radiant or radiation energy; wireless trans-
mitter
-agere- drive, do
The emission of radiation, either spontaneously
from unstable atomic nuclei or as a consequence
of a nuclear reaction.
Radionuclide
English/Latin
radi-radiantorradiationenergy;wirelesstransmitter
A radioisotope; a nuclide that exhibits a certain
amount of radioactivity.
Radiosonde
English/French
-sonde a sounding lead/line
A measurement device that is carried aloft by a
balloon to relay temperature, pressure, and
humidity data from the upper atmosphere.
Radius
Latin
ray- spoke of a wheel
-ius singular
A line segment that connects the center of a circle
or sphere to any point on its outer edge.
Radula
Latin
radere to scrape
Flexible, tonguelike organ in certain mollusks,
having rows of horny teeth on the surface.
Range
German
reng to put in a row, line
The difference between the smallest and largest
values in a distribution.
Raptor
Latin
rapere to seize
A bird of prey; carnivorous bird that hunts its
prey.

Raptor 167
Joseph Meister Had Rabies
On a sunny day in the summer of 1885 at Meissen-
gott, in Alsace, a boy named Joseph Meister was
attacked by a neighborhood dog. The 9-year-old
Joseph was thrown to the ground, and as he tried to
protect his face he was savagely bitten about the
arms. The dog was finally driven off the boy, but the
damage was done. His skin had been pierced by a
rabid dog.
The local physician did all he could. He cauter-
ized and cleaned the wounds, but he knew what
would soon happen to the child. He advised the
mother to take him to Louis Pasteur, a scientist who
was experimenting on rabies in Paris. Though Pas-
teur was not a physician, he was the boy’s best and
only hope.
Once bitten by a rabid animal, the human victim
experiences a brief period of fever and restlessness
before becoming wildly excitable. The infected
individual salivates excessively and a white, frothy
foam appears around the mouth. The muscles of the
throat become highly irritated, with uncontrollable
spasms causing great pain. All the while the victim
experiences an uncontrollable thirst for water but is
unable to drink. This torture continues relentlessly
for up to five days before the victim falls dead as a
result of exhaustion, asphyxia, and paralysis.
What could cause such horrible symptoms?
Rabies was a disease known to the ancients.
Although it was never the blight that the plagues
that ravaged Europe and Asia were, it brought fear
to those who witnessed the agonizing death of its
victims. The Greeks attributed rabies to the wrath
of the gods. Sirius, the Dog Star, in the constella-
tion Canis Major, was believed to be the cause of
the disease. The days during summer in the North-
ern Hemisphere when Sirius rises immediately
before or sets immediately after the sun, referred to
as the “dog days,” were believed to be a time when
normally docile animals would run wild and
become viciously aggressive. Shortly thereafter,
they would convulse, become paralyzed, and die.
In the fifth century BC, the Greek physician
Democritus described the symptoms of rabies, as
did Aristotle two hundred years later. The Romans
in the first century AD cauterized or placed the
ashes of seahorses on the wounds to treat the condi-
tion, but, of course, these treatments were futile.
Pliny the Elder, a Roman naturalist who lived in
the first century AD, wrote on the treatment of
rabies:
It is universally agreed, too, that when a
person has been bitten by a dog and manifests
a dread of water and of all kinds of drink, it
will be sufficient to put under his cup a strip of
cloth that has been dipped in menstrual fluid;
the result being that the hydrophobia will
immediately disappear. This arises, no doubt,
from that powerful sympathy which has been
so much spoken of by the Greeks, and the
existence of which is proved by the fact,
already mentioned, that dogs become mad
upon tasting this fluid.
When Joseph Meister and his mother arrived in
Paris on July 6, Joseph was in very bad shape. His
pain was such that he could barely walk. Pasteur
knew what he had to do, but he needed to consult
with colleagues. According to Pasteur, the numer-
ous trials of his rabies vaccine on animals had
proven to be a resounding success. Later we would
find out otherwise, but nonetheless, this was
Joseph’s last and best chance at survival. A team of
government scientists gave Pasteur their approval
to begin the procedure.
Over the next 11 days, Joseph was injected with
small amounts of the vaccine, which Pasteur had
prepared using the spinal cords of infected rabbits.
Pasteur wrote in his journal:
The death of this child appearing to be
inevitable, I decided, not without lively and
sore anxiety, as may well be believed, to try
upon Joseph Meister, the method which I had
found constantly successful with dogs. Con-
sequently, sixty hours after the bites, and in
the presence of Drs Vulpian and Grancher,
young Meister was inoculated under a fold of
skin with half a syringeful of the spinal cord
of a rabbit, which had died of rabies. It had
been preserved (for) fifteen days in a flask of
dry air. In the following days, fresh inocula-
tions were made. I thus made thirteen inocula-
tions. On the last days, I inoculated Joseph
Meister with the most virulent virus of rabies.
There were side effects—Joseph experienced
bouts of anxiety and depression—but there were no
longer signs of the dreaded disease. And so, after
ten more days of observation, Joseph was sent
home. He had escaped death.
Years later, Joseph Meister would return to Paris
and work as doorman for the Pasteur Institute. He
worked at the institute until the age of 64 in 1940,
when the Nazis invaded Paris. The Germans
ordered Meister to open Pasteur’s crypt. Rather
than obey that order, Joseph Meister put a gun to his
head and ended his own life.

168 Rarefaction
Rarefaction
Latin
rarus- rare
-facere- to make
That part of the sound wave where the particles of
the sound medium are farthest apart.
Rate
Latin
rata according to a fixed proportion
A quantity, amount, or degree of something mea-
sured per unit of time.
Ratiocination
Latin
ratio- reason
-cinari- reckon
To reason using formal logic; to use deductive
reasoning.
Rawinsonde
English/French
-wind- moving air
-sonde a sounding lead/line
A radiosonde used to observe the velocity and
direction of upper-air winds and tracked by a
radio direction-finding instrument.
Reactance
Latin
re- to do something again; go against
-agere to drive, do
Opposition to the flow of alternating current
caused by the inductance and capacitance in a cir-
cuit rather than by resistance.
Reaction
Latin
-agec- to act
A response in opposition to a substance, treat-
ment, or other stimulus.
Reactive
English/Latin
-agec- to act
Tending to participate readily in reactions.
Reagent
English/Latin
-agere a force or substance that causes a change
A substance used in a chemical reaction to detect,
analyze, or produce other substances.
Marie Curie
Eve Curie wrote of her mother, “She was a woman;
she belonged to an oppressed nation; she was poor;
she was beautiful. A powerful vocation summoned
her from her motherland, Poland, to study in Paris,
where she lived through years of poverty and soli-
tude. There she met a man. . . . By the most desper-
ate and avid effort they discovered a magic element,
radium. This discovery not only gave birth to a new
science and new philosophy; it provided mankind
with the means of treating a dreadful disease.”
MarieCuriewasbornMarieSklodovskainPolandon
November 7, 1867. She had a rather distress-filled
youth. Her sister died of typhus and her mother
passed away four years later. After her high school
years Marie sunk into a depressive state.
Marie showed signs of brilliance at a young age.
She possessed an amazing memory and an intellec-
tual curiosity, but attending a university in Poland
was out of the question. She knew that to thrive, she
would have to leave Poland. Years later, in Paris,
after studying physics and chemistry at the Univer-
sity of Paris (Sorbonne), she became the first
woman to teach at that highly prestigious institu-
tion. There she met Pierre Curie, whose title was
Chief of the Laboratory of the School of Physics
and Chemistry of the City of Paris. They married
and together studied radiation and subsequently
discovered the elements radium and polonium.
Her work led to the use of x-rays in World War I.
This remarkable application of radiation allowed
surgeons to more easily find the bullets lodged in
soldiers, giving them a greater chance of survival
through surgery. Her studies with radiation led to
additional research on the role of radiant energy in
the reduction of cancerous growths. Her accom-
plishments led her to become the first person to
receive Nobel Prizes in two different fields of
study, physics and chemistry. This feat has been
matched only by Linus Pauling, who won Nobel
Prizes for Chemistry and Peace.
Ironically, her isolation of the radioactive mate-
rials from the ore pitchblende for the advancement
of science and medicine ultimately led to her own
death from leukemia in 1934. Albert Einstein said
of Madam Curie, “Marie Curie is, of all celebrated
beings, the only one whom fame has not corrupted.”

Reniform 169
Receptor
Latin
reciepere to receive
A group of sensory nerve endings that respond to
threshold energy from a source point.
Recessive
Latin
recedere- to recede
In genetics, refers to an allele that does not dis-
play its phenotype when paired with a dominant
gene.
Reclamation
English/Latin
-clamare- to call or cry out
The act or process of reclaiming; restoration for
the purpose of productivity.
Rectifier
Latin
rectus- straight, direct
A device, such as a diode, that converts alternat-
ing current to direct current.
Rectoclysis
Latin
rectus- straight, direct
-clys, -clysis to wash, washing
Washing or irrigation of the rectum.
Recycle
English/Greek
-kyklos circle, wheel, cycle, rotate
To make ready for reuse; to pass again through a
series of changes or treatments.
Reduction
English/Latin
-ducere- to lead
To decrease the valence of an atom by adding
electrons.
Reflectivity
English/Latin
-flectere- to throw or bend back
The ratio of the energy of a wave reflected from a
surface to the energy possessed by the wave strik-
ing the surface.
Reflux
Latin
-fluere to flow, wave
A flowing back, ebb; the process by which a con-
tainer with boiling liquid is attached to an appara-
tus that continuously returns the vapor for
reboiling.
Reform
English/Latin
-forma shape, figure, appearance
To improve by alteration, correction of error, or re-
moval of defects; put into a better form or condition.
Refraction
English/Latin
-fract- to break
-ion state, quality, or process of
The turning or bending of any wave, such as a
light or sound wave, when it passes from one
medium into another of different optical density.
Regolith
Greek
rhegos- blanket
-lith rock, stone
The layer of loose rock resting on bedrock, con-
stituting the surface of most land.
Relay
English/French
-laier to leave
An electrical device used to control a switch or to
allow a weak current to control a stronger electri-
cal current.
Relief
French
relever to relieve
The difference in height from the lowest to the
highest point.
Renal
Latin
reno- kidney
or character of
Of or relating to the region of the kidneys.
Reniform
Latin
renes- kidney
Being in the shape of a kidney, such as a leaf.

170 Replicase
Replicase
English/Latin
-plicare- to fold
-ase enzyme
An enzyme that catalyzes the synthesis of a com-
plementary RNA molecule from an RNA template.
Replicate
English/Latin
-plicare- to fold
To reproduce or make an exact copy or copies of
genetic material.
Repressor
Latin
-premere- to press back
A protein produced by the regulator gene; it
blocks the transcription of the gene.
Reproduction
English/Latin
-pro- before; forward; for, in front of; in place of
-ducere- to lead
Theactof(re)producingsomethingofthesamekind.
Reside
Latin
residere to sit back, abide, remain
To dwell permanently or continuously.
Resistance
English/Latin
-sistere- to place
-ance brilliance, appearance
A force that tends to oppose or retard motion.
Resistor
English/Latin
-sistere- to place
A component that resists the flow of current in an
electronic circuit.
Resolution
Latin
resolvere- relax, untie
The process of distinguishing the individual parts
of an object.
Resonance
Latin
-sonare- to sound
-ant performing, promoting, or causing a specified
action
The condition that causes a medium to vibrate in
its natural frequency as a result of receiving sound
waves of the same frequency.
Respiration
English/Latin
-spire- to breathe
The molecular exchange of oxygen and carbon
dioxide within the body’s tissues, from the lungs
to the cellular oxidation processes; the act of
inhaling and exhaling.
Response
Latin
-spondere to promise
The reaction by a living organism to a stimulus.
Restitution
English/Latin
-statuere- to set up
The return to or restoration of a previous state or
position after a collision.
Resultant
English/Latin
-saltare to leap
A vector generated through the sum of other vectors.
Retardant
Latin
-tardare- delay, impede
-ant performing, promoting, or causing a speci-
fied action
Acting or intending to delay or impede. This term is
often used with another term, as in “flame retardant.”
Reticulum
Greek/Latin
reticul- net or networklike
System of membranous saccules and channels in
the cytoplasm, often with attached ribosomes.

Ribosome 171
Retina
Latin
retis net
Innermost layer of the eyeball.
Retrovirus
Latin
retro- backward, behind
-virus poison
Agroupofviruseseachofwhichcontainsonestrand
of RNA. The group includes many viruses that may
cause some cancers, as well as the HIV virus.
Revolution
Latin
-volvere- to turn or spin
The movement of one body (planet) around
another body (sun) or a fixed point.
Rex
Latin
rex king
The king; refers to or denotes size or dominance
of a given species (e.g., Tyrannosaurus rex).
Rheumatic
Greek
rheum- flow, watery discharge from the body
once thought to cause aches and pains in joints
Of, relating to, or having the characteristics of
rheumatism.
Rheumatism
Greek
rheumat- flow, watery discharge from the body
once thought to cause aches and pains in joints
Any of a number of pathological conditions lead-
ing to mild to severe aches and pains in the joints.
Rhinencephalon
Greek
rhin- nose
-on a particle
That portion of the cerebrum concerned with
reception and integration of olfactory (smelling)
impulses.
Rhinitis
New Latin
rhin- nose
Inflammationofthemucousmembranesofthenose.
Rhinoceros
Latin
rhin- nose
-keras horn
Any of a family (Rhinocerotidae) of large, heavy-set,
herbivorous perissodactyl mammals of Africa and
Asiathathaveoneortwouprightkeratinoushornson
thesnoutandthickgraytobrownskinwithlittlehair.
Rhinomycosis
Greek
rhin- nose
-myco- (mukes) fungi
Fungal infection of the nasal mucous membranes.
Rhinorrhea
New Latin
rhin- nose
-rhea flow or discharge
Secretions or discharge from the nose.
Rhizobium
Greek
rhiza- root
Any of various nitrogen-fixing bacteria of the
genus Rhizobium that form nodules on the roots
of leguminous plants, such as clover and beans.
Rhizoid
Greek
rhiza- root
Rootlike hair that anchors a plant and absorbs
minerals and water from the soil.
Rhodophyte
Greek
rhodon- rose
-phyte plant
Marine algae with a reddish color or hue.
Ribonucleic acid
German/Latin
ribo(se)- a kind of sugar
A long, single-stranded polymer found in all liv-
ing organisms and involved in genetic transcrip-
tion and protein synthesis.
Ribosome
Greek
ribose- sugar
A minute, round particle composed of RNA and
protein, found in the cytoplasm of living cells and
active in the synthesis of proteins.

172 Rigid
Rigid
Latin
rigere to be stiff
Refers to a system of particles whose positions
remain fixed relative to each other.
Riparian
Latin
ripa- river bank, stream
-an one that is of, or relating to, or belonging to
Relating to or living on or near the banks of a
stream or river.
Robot
Czech
robot worker
A machine in the form of a human being that per-
forms the mechanical functions of a human being
but lacks emotions and sensitivity.
Rodent
Latin
rodere to gnaw
Any member of the order Rodentia, a group of
animals in the class Mammalia characterized by
having fur, four legs, warm blood, and large inci-
sors for gnawing.
Rodenticide
Latin
rodere- to gnaw
A type of pesticide that controls mice, rats, and
other rodents.
Rostrum
Latin
rostrum beak
A beaklike or snoutlike projection.
Rotation
Latin
rota- wheel
The act or process of turning about a center or an
axis.

Saccharide
Sanskrit
sarkara- sugar
Another name for a sugar.
Saccharolytic
Sanskrit/Greek
sarkara- sugar
Capable of hydrolyzing or otherwise breaking
down a sugar molecule.
Sacrum
Latin
sacr- sacred or holy
Compound triangular bone at the base of the
human spine.
Sagittal
Latin
sagitta- arrow
or character of
Relates to the plane that is parallel to the sagittal
suture of the skull.
Salamander
Latin
salamandra slithering
Any member of the order Caudata, having
porous, smooth skin, weak legs, and a tail.
Salt
Old English
sealt salt
A compound created by the neutralization of an
acid with a base or by a chemical reaction
between a metal and a nonmetal.
Saponification
Latin
saponi- soap
-fication to make
The process of saponifying; the decomposition of
a fat by the addition of an alkali that combines
with its fatty acids to form a soap, with the remain-
ing constituent, glycerin, consequently liberated.
Saprophagous
Greek
sapro- rotten, putrid; decay
Feeding on decaying matter; carrion beetles who
feed off of the rotting matter of dead organisms.
Saprophyte
Greek
sapro- rotten, putrid; decay
-phyton plant
A plant living on dead or decaying organic matter.
Saprotroph
Greek
sapro- rotten, putrid, decay
development
Organism that secretes digestive enzymes and
absorbs the resulting nutrients back across the
plasma membrane.

174 Sarcolemma
Sarcolemma
Greek
sarko- flesh, meat
The plasma membrane of a muscle cell.
Sarcoma
Greek
sarko- flesh, meat
-oma tumor
Cancerous tumor derived from connective tissue.
Sarcomere
Greek
sarko- flesh, meat
-mere part, segment
A segment of a striated muscle cell fibril bounded
by Z-disks.
Satellite
French/Latin
satelles- to hang on
-ite component of a part of a body
A celestial body (moon) revolving around
another celestial body (planet).
Saturated
Latin
satur- full
Incapable of holding any more of a substance or
material.
Saurischia
Greek
sauros- lizard
-iskhion hip joint
A dinosaur of the order Surischia characterized by
having the pelvic girdle of a modern-day reptile.
Scapula
Latin
scapulae shoulder blade
A triangular bone forming the dorsal part of the
shoulder.
Schistosome
Greek
skhizein- to cut, split
Any of several chiefly tropical trematodes (worms
of the genus Schistosoma), many of which are par-
asitic in the blood of humans and other mammals.
Schizocarp
Greek
-karpos fruit
Fruit that splits into several closed, one-seeded
portions upon maturation.
Schizocoelus
Greek
-koilos hollow
The type of development found in protosomes;
initially solid masses of mesoderm split to form
coelomic cavities.
Science
Latin
scire to know, knowledge
The observation, identification, description,
experimentation, investigation, and theoretical
explanation of phenomena.
Scientific
Latin
scire- to know, knowledge
Relating to or employing the methodology of science.
Scintillation
Latin
scintilla- spark
A flash of light produced in a phosphor by
absorption of an ionizing particle or photon.
Scion
Old French
cion descendant
A grafted twig or bud.
Sclera
Greek
skleros hard
Outer, white, fibrous layer of the eye that sur-
rounds the eye except for the transparent cornea.
Sclerenchyma
Greek
sklero- hard
-en- in
-khein to pour
A supportive plant tissue that consists of thick-
walled, usually lignified cells.
Scoliosis
Greek
skolios- crookedness
-osis disease or abnormal condition
Abnormal lateral curvature of the vertebral column.
Scorpio
Greek
skorpios scorpion
The constellation (also called the Scorpion) that lies
near Libra and contains the bright red star Antares.

Septum 175
Seamount
Middle English/Latin
see- sea
-mons mountain
A submarine mountain rising more than 500 fath-
oms (3,000 feet) above the ocean floor.
Secretion
Latin
secernere- to set aside
The state or process of secreting a fluid. Typically
these substances are not waste products; they
include hormones, mucus, and enzymes.
Sedative
Latin
sedates- to calm
A drug that reduces excitability and calms a person.
Sediment
Latin
sed- sit
fied) action
To sit, sink down; the matter that settles to the
bottom of a liquid.
Sedimentation
Latin
sed- sit
fied) action
The act or process of depositing sediment or
gravel as a result of some outside force.
Seismograph
Greek
seismos- to shake
Instrument used to detect and record seismic
waves produced by earthquakes.
Seismologist
Greek
seismos- to shake
-logist a person who studies
A person who studies earthquakes.
Selenium
Greek
selene- moon
A nonmetallic element resembling sulfur and
obtained primarily as a by-product of copper
refining; used in photocells.
Semipermeable
Latin
semi- half
-per- through
-meare- to glide
Partially permeable; refers specifically to a mem-
brane that allows smaller objects to pass through
while prohibiting larger ones.
Senescence
Latin
sen- old age
-esce- beginning, becoming
The sum of processes involving aging, decline,
and eventual death.
Sensitivity
Latin/Greek
sensus- sense
-ive- performing an action
The capacity of an organism to be aware of a
stimulus.
Sepsis
Greek
sepein- to make rotten, putrefactive
A poisoned condition resulting from pathological
organisms or their toxins in the circulatory system.
Septic
Greek
Relates to the process of living tissue becoming
poisoned or rotten as a result of a pathological
organism.
Septicemia
Greek
-haimo- relating to blood or blood vessels
plurals
A systemic disease caused by pathogenic organ-
isms or their toxins in the bloodstream; also
called blood poisoning.
Septum
Latin
saepire- to enclose
A partition or membrane that separates one cavity
or hollow from another.

176 Sessile
Sessile
Latin
sessus- to sit
Without petiole or pedicel—attached directly to
the base; fixed, nonmotile animal.
Setae
Latin
seta bristle
Slender, usually rigid or bristly, and springy
organ or part of animal or plant.
Sextant
Latin
sextus sixth
An instrument so named because it is a sixth of a
circle. It is used to determine latitude and longi-
tude by measuring the altitude of a star or the sun
above the horizon.
Shadow zone
Old English
sceadu shade, shadow
The region on the earth’s surface ranging from
about 7,000 to 10,000 miles from an earthquake
in which a seismograph detects no S waves and
few, weak P waves.
Sidereal
Latin
sidereus- constellation, star
or character of
Of, relating to, or concerned with the stars or con-
stellations; stellar.
Sideropenia
Greek
sideros- iron
An abnormally low concentration of serum iron
in the blood.
Silicate
Latin
silex- hard stone flint
Any of a large group of minerals, forming over
90% of the earth’s crust, that consist of SiO2 or
SiO4 groupings combined with one or more met-
als and sometimes hydrogen.
Silurian
Celtic
silures- a tribe of Wales
-an one that is of, or relating to, or belonging to
Geologic period in the Paleozoic era that marked
the first appearance of air-breathing animals.
Silver
Middle English/Assyrian
siolfor to smelt, refine
sarapu refined silver
The metallic element with atomic number 47,
highly valued for its luster.
Simultaneous
Latin
simul- at the same time
-eous having the quality of, relating to
Happening, existing, or done at the same time.
Sinoatrial node
Latin
sinus- hollow
-atri- open area, central court, hall, entrance, or
main room of an ancient Roman house
A small mass of cardiac tissue located in the pos-
terior wall of the right atrium, sometimes referred
to as the pacemaker.
Sinus
Latin
sinus hollow
A cavity or depression formed by a series of
curved surfaces within a living organism, as in the
human skull.
Siphonaptera
Latin/Greek
siphon- siphon
-apteros wingless
Small, wingless, bloodsucking insects with
mouthparts adapted for siphoning body fluids
from their victims; fleas.
Sirenia
Greek
siren- group of female, partly human creatures in
Greek mythology that lured mariners to destruc-
tion by their singing
plurals
Herbivorous marine mammals, including the
manatee and the dugong.
Skeleton
Greek
skeletos dried up
The bony framework of the body that provides
structure, protection, storage of minerals, and an
environment for hematopoeisis.
Society
Latin
socius companion, fellowship

Speciation 177
An organized population or colony, sometimes
having a division of labor.
Sociobiology
Latin
socius- companion or partner
bodies of knowledge
The study of the biological basis of all social
behavior.
Soil
Latin
solium seat, soil
The top layer of the earth’s surface, consisting of
rock and mineral particles mixed with organic
matter.
Sol
Latin
sol one, alone, or only
Colloid of very small, solid particles dispersed in a
liquid that retains the physical properties of a liquid.
Solar
Latin
sol- the sun
Of, relating to, or proceeding from the sun.
Solenoid
Greek
solen- pipe
A coil of wire that acts like a magnet when a cur-
rent passes through it.
Solid
Latin
solidus firm, unyielding, whole, entire
Matter that has both a definite shape and a defi-
nite volume.
Solstice
Latin
sol- the sun
-status to come to a stop, to stand
The two points along the earth’s elliptical orbit
where the sun’s distance from the equator is greatest.
Soluble
Latin
solvere- to loosen
-able/-ible capable, be inclined to, tending to,
given to/capable
Describes the ability to be homogeneously mixed
in another substance.
Solution
Latin
solvere- to loosen
The process of forming a homogeneous mixture
of any combination of solids, liquids, and gases.
Somatic
Greek
soma- (somatiko) body
Having to do with the body or body cavities or
cells other than reproductive cells.
Somatotropin
Greek
stimulus
Hormone released by the anterior pituitary that
stimulates growth in humans.
Somnambulism
Latin
somnia- sleep; dream
-ambulate- walk, take steps, move around
Sleepwalking or the ability to perform activities
normally associated with being awake while
actually sleeping.
Sonoluminescence
Latin
sonus- sound
-lumen- light
The production of light as a result of the passing
of sound waves through a liquid medium. Light is
formed when bubbles in the liquid burst and
release energy.
Sorus
Greek
soros a heap
A cluster of sporangia borne on the underside of a
fern frond.
Spathe
Latin
spatha a flat blade
A large, leaflike part enclosing a flower cluster.
Speciation
Latin
species- particular kind
Emergence of a new species during evolutionary
history.

178 Species
Species
Latin
species particular kind
A taxonomic unit ranking below a genus and des-
ignated by a binomen consisting of its genus
name and the species name.
Specimen
Latin
specere to look at, appearance
A small sample of something intended to show
the nature of the whole.
Spectrochemical
Latin/Greek
specere- to look at, appearance
-khemeia a substance with a distinct molecular
composition
Pertains to a series listing ligands based on their
energy strengths; these differences cause differ-
ent colors to be emitted.
Spectrophotometry
Greek
-photos- light, radiant energy
The process of using an instrument to measure the
intensity of various wavelengths of radiant energy.
Spectroscopy
Greek
-scopium to look at, examine
Methods of studying substances exposed to some
sort of exciting energy.
Spectrum
Latin
specere to look at, appearance
The distribution of energy emitted by a radiant
source, as by an incandescent body, arranged in
order of wavelength.
Speed
Old English
sped swiftness
The scalar quantity used to measure displacement
per unit time.
Speleothem
Greek
spelaion cave
General name for any cave formation.
Sphenoid
Greek
sphen- wedge, wedge shaped
The sphenoid bone or relating to the sphenoid
bone; wedge shaped.
Sphincter
Greek
sphingein to bind tight
A ringlike muscle whose action resembles that of
the drawstring of a bag. It normally serves to con-
strict an opening (mouth, anus, or arteriole) or,
when relaxed, to enable access to the passage.
Spiracle
Latin
spir- breath of life, breath, breathing; mind, spirit,
courage
-cle small
The external openings of the insect breathing (tra-
cheal) system, found along the abdomen.
Spirochete
Greek/Latin
speira- coil
-chaeta bristle hair
Any of the various slender, spiral-shaped, motile
bacteria.
Spirogyra
Greek
speira- coil
-guros ring
Any of various filamentous freshwater green
algae of the genus Spirogyra, having chloroplasts
in spirally twisted bands.
Spongocoel
Greek
spongos- sponge
-koilos hollow
Central cavity in sponges that opens to the exte-
rior by an osculum.
Sporangium
Greek
sporos- seed
-angeion- vessel
Spore-containing structure; a sac or case in which
spores are produced.
Sporophyte
Greek
spora- seed
-phuto plant
A stage in a plant’s life cycle during which spores
are produced.
Sporozoan
Greek
spora- seed
-zoan animal, animal-like

Stenocrotaphia 179
Member of the class Sporozoa, consisting of non-
motile, single-celled parasitic organisms.
Stability
Latin
stabilis- to stand
Resistance to chemical change or to physical
disintegration.
Stalactite
Greek
stalaktos- dropping or trickling
An icicle-shaped, secondary mineral deposit that
hangs from the roof of a cave.
Stamen
Latin
stamen thread
Reproductive, pollen-producing organ of a vascu-
lar plant, composed of a filament and an anther.
Staphylococcus
Greek
staphylo- cluster
-coccus of spherical or spheroidal shape
Spherical parasitic bacterium, usually occurring
in grapelike clusters.
Static
Greek
statos- standing, stay, make firm, fixed
Of or relating to bodies at rest or forces that bal-
ance each other.
Stationary
Greek
-ary of or relating to or connected with
Incapable of being moved, fixed; nonmotile
organisms.
Statocyst
Greek
A very small, fluid-filled organ found in many
invertebrates that orients the body in relation to
gravity.
Stearoptene
Greek
steat- fat, tallow
-ptenos volatile, winged
The more solid component of a volatile oil; it sep-
arates out as a whitish, crystalline solid as it cools
to room temperature.
Steatohepatitis
Greek
steat- fat, tallow
-hepat- liver
Disease condition that is characterized by fatty
deposits in the liver, that may or may not be
caused by excessive alcohol use, and that has few
symptoms that can be readily diagnosed.
Stegnosis
Greek
stegn- constriction, obstruction
A condition causing the stoppage of secretions;
constriction, constipation.
Stegosaur
Greek
stegos- roof
-sauros lizard
Herbivorous dinosaur existing in the Jurassic to
the Cretaceous periods and characterized by a
double row of boney plates along the dorsal side,
long rear legs, and a small head and neck.
Stele
Greek
stele pillar
The central core of tissue in the stem or root of a
vascular plant.
Stenobenthic
Greek
stenos- narrow
-benth- deep; the fauna and flora of the bottom of
the sea
Living within a narrow range at or near the bot-
tom of the sea.
Stenocoriasis
Greek
stenos- narrow
-core- (corium) skin
-iasis a process or a pathological condition
The abnormal contraction of the pupil of the eye;
a symptom of a pathological condition.
Stenocrotaphia
Greek
stenos- narrow
-crotaphion- pulse, beat
plurals
Narrowness of the temporal region.

180 Stenohaline
Stenohaline
Greek
stenos- narrow
-halo- salt
Refers to organisms that are capable of tolerating
only slight variations in salinity.
Stenothermal
Greek
stenos- narrow
or character of
Describes an organism tolerant of only a narrow
range of temperatures.
Stenothorax
Greek
stenos- narrow
-thoraces chest
Abnormal narrowness of the chest.
Stephanion
Greek
stephanos- crown
The point on the side of the cranium at which the
coronal suture meets the superior temporal line.
Steradian
Greek
ster- solid
-radi- ray, spoke of a wheel
Measurement of solid angles, equivalent to the
angle subtended at the center of a sphere by an
area on its surface equal to the square of its radius.
A full sphere subtends 4␲ steradians.
Stereocilium
Greek
stereos- three-dimensional, solid, firm, hard
-cili- a small hair
A nonmotile protoplasmic filament on the free
surface of a cell; found on hair cells of the inner
ear and on pseudostratified epithelial cells of the
male epididymis.
Stereopsis
Greek
-opisi vision
Stereoscopic vision allowing for depth percep-
tion and visual acuity.
Stereoscopic
Greek
-skopein- to view, examine
Pertaining to two images of the same scene, dif-
fering slightly in point of view, that are each seen
by one eye, giving the effect of solidity.
Sternum
Greek
sternon- chest, breast, sternum, the breast bone
A long, flat bone articulating with the cartilages
of the first seven ribs and with the clavicle, form-
ing the middle part of the anterior wall of the tho-
rax, and consisting of the corpus, manubrium,
and xiphoid process.
Stethoscope
French/Greek
stethos- chest
-skopein to view, examine
Any of a group of instruments designed to
amplify the sounds of the chest, such as heartbeat
or respiration.
Stigma
Greek
stizein tattoo mark; to prick
A small pore, mark, or spot, such as the respira-
tory spiracle of an insect.
Stipule
New Latin
stipula trunk
Either of a pair of appendages borne at the base of
the leafstalk in many plants.
Stoichiometry
Greek /English
stoicheious- element
-metria (metron) the process of measuring; to
measure
A branch of science that deals with the applica-
tion of the laws of definite proportions and of the
conservation of matter and energy to chemical
activity.
Stolon
Latin
stolo shoot
A shoot that bends to the ground or that grows
horizontally above the ground, and that produces
roots and shoots at the nodes.

Sublimation 181
Stomach
Greek
stomakhos gullet
The enlarged portion of the alimentary canal lying
between the esophagus and the small intestine.
Stomata
Greek
stoma mouth
One of the minute pores in the epidermis of a leaf
or stem through which gases and water vapor pass.
Stratigraphy
Latin
stratum- horizontal layer; stretched, spread out;
layer, cloud layer
The study of the arrangement, distribution, and
deposition of rocks in layers.
Stratosphere
Latin
layer, cloud layer
-sphaire to surround
The second lowest layer of earth’s atmosphere; the
ozone layer is located in the upper stratosphere.
Stratovolcano
Latin
layer, cloud layer
-vol’nus fire, flames (named after the Roman god
of fire)
A volcano built up from alternating layers of rock
and lava.
Stratus
Latin
layer, cloud layer
Featureless sheets of clouds; horizontal, spread-
out layers of grayish-colored clouds.
Strepsirhini
Greek
streptos- twisted chain, turn
-rhino nose, nasal
Suborder containing seven families of arboreal
primates, formerly called prosimians, concen-
trated on Madagascar and having comma-shaped
nostrils, a long nonprehensile tail, and a second
toe provided with a claw.
Streptococcus
Greek
streptos- twisted chain, turn
-kokkosofsphericalorspheroidalshape,grain,seed
Spherical bacteria that occur in pairs or chains.
Striation
Latin
stria- thin narrow groove or channels, bands
In biology, a group of protein bands found in skel-
etal muscle that are involved in muscular contrac-
tions. In earth science, one of a number of parallel
lines or scratches on the surface of a rock that
were inscribed by rock fragments imbedded in
the base of a glacier as it moved across the rock.
Stromatolite
Greek
stroma- living on a bed; spread out
-lite combining form used in naming of minerals
Large mats and mounds composed of billions of
photosynthesizing cyanobacteria that dominated
the Proterozoic’s shallow oceans.
Structure
Latin
structura part
A part of the body, such as the heart, a bone, a
gland, a cell, or a limb.
Subcutaneous
Latin
sub- under or below
-cutis- skin
Refers to tissue or other object located just below
the dermis or skin.
Subduction
Latin
sub- under or below
-ducere- to lead
Pertains to a long narrow zone associated with
oceanic trenches, where one plate descends
beneath another.
Sublimate
Latin
sublimus- up to, elevate, uplifted
To purify or refine by subliming; to change matter
from the solid state to the gaseous state or from
the gaseous state to the solid state without an
intervening liquid state.
Sublimation
Latin
sublimus- up to, elevate, uplifted
The process of changing a solid substance
directly into a vapor without it first passing
through the liquid state.

182 Sublime
Sublime
Latin
sublimus up to, elevate, uplifted
To go directly from a solid to a gas without going
through the liquid phase.
Subscript
Greek
sub- under or below
-scribere writing
A symbol written below another symbol or letter.
Substance
Latin
sub- under or below
-stantia- essence, material
-ance state, quality
Amaterialproducedbyorusedinachemicalprocess.
Subterranean
Latin
sub- under or below
-terra- earth
Refers to that which is found beneath the earth’s
surface.
Succession
Latin
succedere- to follow after
Theactoffollowinginorder;followingconsecutively.
Sugar
Middle English
sugre sugar
Any of various water-soluble compounds that
vary widely in sweetness and include the
oligosaccharides.
Supercell
Latin
super- superior in size, quality, number, or
degree; exceeding the norm
-cella small room, compact, chamber
Self-sustaining, extremely powerful storm char-
acterized by intense rotating updrafts.
Superconductivity
Latin
-conducere- to bring together
The flow of electric current without resistance in
certain metals, alloys, and ceramics at tempera-
tures near absolute zero, and in some cases at tem-
peratures hundreds of degrees above absolute zero.
Supercooling
Latin
-cole- becoming less warm
-inde the act of
Cooling a liquid to a temperature below that at
which crystallization would normally occur but
without the separation of a solid.
Supernova
Latin
-nova new
A rare celestial phenomenon involving the explo-
sion of most of the material in a star, resulting in
an extremely bright, short-lived object that emits
vast amounts of energy.
Surfactant
Old French
sur- above
-face- outward appearance
-agere to do
A surface-active substance designed to make a sur-
face “wetter”; the fluid layer of the alveolar sacs of
the lungs that makes the exchange of gases possible.
Susceptible
Latin
sus- (sub) below, under, beneath
-capere- catch, seize, take hold of, contain
-able/-ible capable, be inclined to, tending to,
given to/capable of
Likely to be affected; permitting an action to be
performed.
Suspension
Latin
suspendere- to cause to hang
A system consisting of a solid dispersed in a
solid, liquid, or gas, usually in particles of larger
than colloidal size.
Sustainable
Latin
-tenere- to hold, grasp, have
Of, relating to, or being a method of harvesting or
using a resource so that the resource is not
depleted or permanently damaged.

Systole 183
Symbiosis
Greek
sym- with, together
The living together of two different species in an
intimate relationship. The symbiont always bene-
fits; the host may benefit, may be unaffected, or
may be harmed (mutualism, commensalism, and
parasitism, respectively).
Symmetrical
Greek
sym- with, together
-meter- (metron) instrument or means of measur-
ing; to measure
or character of
Regular as to the number of its parts; correspond-
ing units of similar structure that exist on either
side of a central axis.
Synapse
Greek
syn- together, united
-haptein- to fasten
Junction between two nerve cells, allowing the
transfer of nerve impulses from the axon terminal
of one neuron to another neuron or cell.
Synchronous
Greek
-khronos- time
Occurring or existing at the same time; moving or
operating at the same time.
Syncline
Greek
-klinein to lean
A fold in rocks in which the rock layers dip
inward from both sides toward the axis.
Syncytial
Latin
or character of
Pertaining to a cytoplasmic mass that is multinu-
cleated and lacks intercellular boundaries.
Syndiotactic
Greek
syndio- two together
-taktos ordered
Refers to the type of orientation of the methyl
groups on a polypropylene chain in plastics—in
this case alternating orientation.
Syndrome
Greek
-dramein (dromos) to run
A group of signs and symptoms that occur
together and characterize a particular abnormality.
Synecology
Greek
-oikos- house
bodies of knowledge
Ecology of communities as opposed to individual
species.
Synovial joint
Greek
-ovo- egg
Freely moving joint in which two bones are sepa-
rated by a cavity.
Synthesis
Greek
-tithen- to put
The combining of separate elements or sub-
stances to form a coherent whole.
Systematics
Greek
-histanai- set up
The systematic classification of organisms and the
evolutionary relationships among them; taxonomy.
Systole
Greek
sustellein to contract
The rhythmic contractions of the ventricles of the
heart that cause blood to be pumped from the
heart into the aorta and the pulmonary arteries.

Tachycardia
New Latin
takhus- fast, swift
plurals
Faster than normal heart rate, usually calculated
over 100 beats per minute in the resting state for
adults.
Tachyon
English
takhus- fast, swift
-on a particle
A hypothetical subatomic particle that travels
faster than the speed of light.
Tachypnea
Greek
takhus- fast, swift
-pnein breath
Breathing very rapidly.
Tarsal
Greek
tarsus- ankle
-al of the kind of, pertaining
to, having the form or character of
A bone of the ankle; of or relating to the ankle.
Taxon (taxa)
Greek
taxis order, arrangement
Any taxonomic group or entity: kingdom, phy-
lum, class, order, family, genus, or species.
Taxonomy
Greek
taxis- order, arrangement
-nom (nemein) to dictate the laws of, knowledge,
usage, order
The classification of organisms in an ordered sys-
tem that indicates natural relationships.
Technology
Greek
tekhne- skill, craft
bodies of knowledge
The application of science to situations usually,
but not exclusively, associated with commerce
and industry.
Tectonic
Greek
tekton- builder
-ic (ikos) relating to or having some characteristic
of
In geology, relating to, causing, or resulting from
structural deformation of the earth’s crust. Study
of the earth’s structural features.
Telencephalon
Greek
tele- far off, distant
The anterior portion of the prosencephalon, con-
stituting the cerebral hemispheres and composing
with the diencephalon the prosencephalon.

Tephra 185
Telescope
Greek
-skopos watcher
An optical instrument used for viewing distant
objects by means of the refraction of light rays
through a lens.
Telophase
Greek
telos- end
-phasis appearance
The final of the four stages of nuclear division in
mitosis and each of the two divisions in meiosis.
Telson
Greek
telson limit
The rearmost segment of the body of certain
arthropods; an extension of this segment, such as
the middle lobe of the tail fan of a lobster or the
stinger of a scorpion.
Tendon
Greek
tenon- tendon, sinew, to stretch
A band of tough, inelastic fibrous tissue that con-
nects a muscle with its bony attachment.
Tenodesis
Greek
tenon- tendon, sinew, to stretch
-desis binding, fixation
The surgical fixation of a tendon to a bone.
Tenoplasty
Latin/Greek
tenon- tendon, sinew
Reparative or plastic surgery of the tendons.
Tension
Latin
tension- an extension or length
A force supplied by a rope or chain whose direc-
tion is away from the load.
Tentacles
Latin
tentare to feel, try
A flexible extension, such as one of those sur-
rounding the mouth or oral cavity of the squid,
used for feeling, grasping, or locomotion.
Tephra
Greek
tephra ash
The solid substance ejected from a volcanic eruption.
Thomas Edison, the Great American Inventor
Few inventors in history were as prolific as Thomas
Edison. When he was born, in 1847, the world was
illuminated by candle and fire. When he died, in
1931, the world glowed in incandescent light.
Though not his invention, he perfected the idea and
came upon the necessary elements that would give
light without burning out too soon.
Edison conducted most of his research at Menlo
Park in New Jersey. There he would devote his life
to producing some of the most widely used technol-
ogy in history. Edison did not work alone. He had
brilliant assistants with a single overriding objec-
tive: invent and produce. William Hammer, one of
Edison’s assistants, was the person in charge of per-
fecting the light bulb, and he did a remarkable job.
In the year after the development of Edison’s bulb,
the Edison Lamp Works produced over 50,000
lamps.
Edison held 1,093 patents. With a steady flow of
inventions, from his first patent (“Electrographic
Vote-Recorder” in June 1869) to his last (“A Holder
for Articles to Be Electroplated,” submitted in May
1933), Edison and his assistants invented and pat-
ented such gadgets as the printing telegraph, the
electric switch, electromagnetic telegraphic instru-
ments, the typing wheel for telegraphs, the galvanic
battery, the speaking machine, the phonograph, the
vacuum pump, the electric generator, the typewriter,
the electric meter, the electric indicator, the electric
railway, the electrical transmission of power, pho-
nogram blanks, the motion picture camera, railway
signaling, the voltaic battery, the electric locomo-
tive, the magnetic separator, the gas purifier, the
cement kiln, an electronic system for automobiles, a
process for constructing concrete buildings,
improvements to the telephone, and on and on.
Thomas Edison died in 1931. He, along with a
few other men in his lab, changed American society
forever. Through his inventions and his strong busi-
ness sense, he managed to get his inventions manu-
factured at a cost that was affordable to many. In a
tribute to his passing, the lights were dimmed for
one minute on October 21, 1931, a few days after
his death.

186 Teratological
Teratological
Greek
terat- marvel, omen, monster
-logo- talk, speak
or character of
Monstrous, relating to monstrosity; the biological
study of birth defects.
Terrain
Latin
terrenus of the earth
A series of related rock formations.
Tertiary
Latin
tertius- third
First period of the Cenozoic era, extending from
the beginning of the Paleocene epoch over 58
million years ago to the end of the Pliocene epoch
2 million years ago.
Tetrad
Greek
tetras four
A group or set of four homologous chromosomes.
Tetrahedron
Greek
tetra- four faced
-hedron head
A polyhedron with four faces; a Platonic solid P5.
Thallophytes
Greek
thallos- young green shoot
-phyte a plant
A major group of organisms formerly belonging
to the plant kingdom. They lack true roots, stems,
and leaves. Representative samples include algae,
fungi, and mosses.
Thallus
Greek
-us thing
A plant that possesses an undifferentiated stem
and lacks true vascular tissue.
Thermoacidophile
Greek
thermos- combining form of “hot” (heat)
-acido- of or related to an acid
preference for
An organism that thrives in a strongly acidic envi-
ronment at high temperatures.
Thermocline
Greek
The transitional layer between warm surface waters
and the cold bottom water of oceans or lakes.
Thermodynamic
Greek
thermos- combing form of “hot” (heat)
-dynamique- powerful
Characteristic of or resulting from the conversion
of heat into other forms of energy.
Thermograph
Greek
A thermometer that records temperatures inde-
pendently of humans by graphing the data on
paper or recording the data electronically.
Thermometer
Greek
ing; to measure
A device usually consisting of a graduated glass
tube filled with either alcohol or mercury that is
used to measure temperature.
Thermophile
Greek
preference for
Any group of organisms that have adapted to and
thrive in environments of extreme heat, usually
over 45 degrees Celsius.
Thermosphere
Greek
The outermost layer of the earth’s atmosphere.
Thermostat
Greek
-statos standing, stay, make firm, fixed, balanced
An automatic device for regulating temperature.
Thigmotropism
Greek
thigma- to touch
stimulus

Titrate 187
The turning or bending response of an organism
upon direct contact with a solid surface or object.
Thoracic
Greek
thorakikos- thorax, chest
Of, pertaining to, or situated in or near the chest.
Thoracocentesis
Latin
thorakikos- thorax, chest
-cente- puncture
Aspiration of the pleural cavity. A surgical proce-
dure where the chest wall is punctured to allow
for the drainage of fluids from the chest.
Thorax
Greek
thorakikos thorax, chest
The cage of bone and cartilage where the primary
organs of the respiratory system reside. Formed
ventrally by the sternum and costal cartilages and
dorsally by the twelve thoracic vertebrae con-
nected to the dorsal parts of the twelve ribs.
Thrombocyte
Greek
thrombo- clot, blood clot
A cell, specifically platelets responsible for initi-
ating the clotting of blood.
Thrombocytopenia
Greek
A reduced number of platelets in the blood.
Thrombosis
New Latin
Formation of a clot in a blood vessel.
Thrust
Old Norse
thrysta to tire
The force provided to drive an object through a
medium, such as an airplane through air.
Thylakoids
Greek
thylakos- sack
Fattened sac within a granum whose membrane
contains chlorophyll and where the light-depen-
dent reactions of photosynthesis occur.
Thymine
Greek
thym(ic) acid- acid from the thymus
An essential nitrogenous base found in DNA.
Thymus
Greek
thumos wartlike outgrowth
A tiny lymphatic gland located behind the ster-
num. It is active in young people and is mostly
involved with T cell differentiation. It diminishes
in size and becomes vestigial in adults.
Thyroid
Latin
thureos- oblong shield, door
An endocrine gland located laterally to the tra-
chea in mammals; it produces various hormones,
including triiodothyronine and calcitonin.
Thysanoptera
Greek
thysanos- fringe
-pteron feather, wing
An insect order classified as being minute to
small, with long, narrow bodies and broadly
fringed wings (also know as thrips).
Thysanura
Greek
thysanos- fringe
-ura tail
Silverfish; wingless, quick-moving, flattened
insects that lack metamorphosis and are consid-
ered by humans to be a pest species.
Tide
Old English
tima division of time
The periodic variation in the surface level of the
oceans caused by the gravitational attraction of
the moon and the sun.
Time
Anglo Saxon
tima time, hour, or season
The period between two events.
Tinnitus
Latin
tinnire to ring
A ringing sound in the ears, the cause of which is
unknown.
Titrate
French
titre- concentration of a substance

188 Titration
To determine the concentration of a substance by
titration.
Titration
Latin
titre- concentration of a substance
The process of determining the concentration of a
substance in solution by adding to it a standard
reagent of known concentration in carefully mea-
sured amounts until a reaction of definite propor-
tion is completed.
Tongue
Latin
tunge tongue
A muscular organ that is usually attached to the
floor of the mouth.
Tonsil
Latin
toles tonsil
Mass of lymphoid tissue in the back of the mouth
and the throat and on the rear of the tongue.
Topography
Greek
topos- place
Theconfigurationofasurface,includingitsreliefand
the position of its natural and man-made features.
Torque
Latin
torquere to twist
The moment of a force or the measurement of a
force’s tendency to produce torsion or rotation
around an axis.
Toxic
Greek
toxikos- poison
Having to do with poison or something harmful to
the body.
Toxicity
Greek
toxikos- poison
Of, relating to, or caused by a poison or toxin.
Toxicomania
Greek/English
toxikos- poison
-mania obsessive preoccupation with something;
madness, frenzy; obsession, or abnormal desire for
An intense craving for poisons; an urge to poison
oneself.
Trachea
Greek/Latin
trakheia rough
Main trunk of the system of tubes by which air
passes to and from the lungs.
Trait
Latin
tractus drag, drawing out, line
A distinguishing quality; an inherited characteristic.
Trajectory
Latin
traicere- to cause to cross.
The path followed by a projectile.
Transcription
Latin
trans- across or through
-scribere to write down
A process in which DNA serves as a template for
RNA formation.
Transduction
Latin
transducere- transfer
The transfer of genetic material from one micro-
organism to another by a viral agent.
Transfer
Latin
-ferre to carry
To convey or cause to pass from one place, per-
son, or thing to another.
Transformation
Latin
-forma- shape
The alteration of a bacterial cell caused by the
transfer of DNA from another bacterial cell.
Transfusion
Latin
-fundere- to pour
The act of instilling, moving, or transferring a
substance from one vessel to another.
Transgenesis
Latin

Triceps 189
Integration into a living organism of a foreign
gene that confers upon the organism a new prop-
erty that it will transmit to its descendants.
Transgenic
Latin
Refers to an organism that contains genes from
another species, where the genes contain foreign
DNA.
Translation
Latin
-latus- brought
The process by which mRNA directs the amino
acid sequence of a growing polypeptide during
protein synthesis.
Translocation
Latin
-locus- place
The rearrangement of genetic material within the
same chromosome, or the transfer of a segment of
one chromosome to another, nonhomologous one.
Translucent
Latin
-lucere- to shine
Transmitting light but causing sufficient diffusion
to prevent the perception of distinct images.
Translunar
Latin
-luna- moon
Extending beyond the moon or its orbit around
the earth.
Transmission
Latin
-miss- to let go or to send
The process of causing to pass through, be con-
veyed, or be sent out.
Transpiration
Latin
-spir- to breathe
The evaporative loss of water from a plant.
Transplant
Latin
-plantare to plant
To uproot a plant from one area to another, or to
remove an organ or tissue from an animal and
place it in another.
Transport
Latin
-portare carry
The movement or transference of biochemical
substances from one site to another.
Transverse
Latin
-vertere to turn
Situated or lying across; crosswise.
Trematode
Greek
tremat- perforation
-hodos wave
A class of parasitic flatworms that attach them-
selves to hosts by hooks or suckers.
Triassic
Latin
trias- three
Of or belonging to the geologic time, system of
rocks, or sedimentary deposits of the first period
of the Mesozoic era, characterized by the diversi-
fication of land life, the rise of dinosaurs, and the
appearance of the earliest mammals.
Triboluminescence
Greek/Latin
tribein- to rub
-lumen- light
The production of light taking the appearance of
tiny sparks that are observed in the dark in some
minerals when a hard point is dragged across the
surface of the mineral.
Triceps
Latin
tri- three
-caput head
A muscle with three points of origin.

190 Triceratops
Triceratops
Greek
tri- three
-keras- horn
-ops eye, face
A herbivorous dinosaur of the genus Triceratops,
of the Cretaceous period, having a bony plate
covering the neck, a large horn above either eye,
and a small horn on the nose.
Trichinella
Greek
trichinos- made of hair
-ella little
One of the group of parasitic nematodes that are slen-
der and hairlike; roundworms that cause trichinosis.
Trichocyst
Greek
trichinos- made of hair
A threadlike stinging or grasping structure pos-
sessed by some ciliates and other protists that is
used for capturing prey.
Trichoptera
Greek
trichino- made of hair
-pteron feather, wing
The four-winged insect order whose species are
found near lakes and streams; caddisflies.
Trichroism
Greek
tri- three
-khros- color
The property possessed by certain minerals in
which three different colors are displayed when
the mineral is viewed from three different direc-
tions under white lights.
Triclinic
Greek
tri- three
Having three unequal axes intersecting at oblique
angles.
Tricuspid
Greek
tri- three
-cuspis- sharp point, cusp
Structure having three cusps; the molars (teeth)
and the tricuspid valve of the human heart.
Trigeminal
Greek
tri- three
-gemin- twin, double
or character of
The main sensory nerve of the face and motor
nerve for the muscles of mastication.
Trisomy
Greek
tri- three
-soma- (somatiko) body
Abnormal condition of having three copies of a
chromosome rather than the normal two in a
somatic cell.
Trophozoite
Greek
trophos- (trophein) to nourish, food, nutrition;
development
-zoion animal, living being
The adult, active feeding stage of unicellular
organisms in the class Sporozoa.
Tropism
Greek
trope- bend, curve, turn, a turning; response to
stimulus
The turning or bending movement of an organism
toward or away from an external stimulus.
Tropopause
Greek
stimulus
-pausis stop
Atmospheric region between the troposphere and
the stratosphere.
Troposphere
Greek
stimulus
The lowest region of the atmosphere between the
earth’s surface and the tropopause, characterized by
decreasing temperature with increasing altitude.
Trough
Middle English
trog wooden vessel
The minimum point in a wave or alternating signal.
Tsunami
Japanese

Tyrannosaur 191
tsu- port
-nami wave
A large ocean wave caused by an underwater
earthquake or volcanic eruption.
Tubule
Latin
tubus- pipe
-ule little, small
A very small tube or tubelike structure.
Tufa
Latin
tufos tuff
Calcareous lime deposits usually formed as pre-
cipitates from springs with high concentrations of
calcium; unusual formations of lime deposits.
Tumor
Latin
tumere to swell
An abnormal growth of tissue characterized by a
proliferation of cells serving no useful purpose.
Tympanic
Greek
tumpanon- drum
Relating to the membrane, a diaphragm-like
structure that is external on some insects and
internal in mammals.
Tyrannosaur
Greek
turannos- tyrant
-sauros lizard
A large dinosaur with small forelimbs, a large
head, and a strong tail that existed during the
Upper Cretaceous period in North America.

Ulcer
Latin
ulcus open sore
Lesion of the skin or mucous membrane in which
bleeding usually occurs and necrosis of the sur-
rounding tissue often occurs.
Ultraviolet
Latin
ultra- beyond, to an extreme degree
-violet shortest ray on the visible spectrum
Lying just beyond the violet end of the visible
spectrum.
Umbra
Latin
umbra shadow
The completely dark portion of the shadow cast by
the earth, moon, or other body during an eclipse.
Undifferentiated
Latin
un- not
-differens different
Refers to cells during embryonic growth that
have not yet developed into organs and tissues
with specialized functions.
Ungulate
Latin
unguis- hoofed, clawed, nail
Of or belonging to the former order Ungulata;
hooved mammals such as horses, cattle, deer, and
swine.
Unicellular
Latin
uni- same, one
-cellul- cell, small room
Plant and animal-like organisms that have or con-
sist of one cell; to be one-celled.
Uniform
Latin
uni- same, one
-forma shape
Being always the same, as in character or degree;
unvarying.
Uniparous
Latin
uni- same, one
-para- to bring forth, to bear
Refers to animals that produce one offspring at a
time or to plants that form a single axis at each
branching.
Unit
Latin
unus one
A determinate quantity adopted as a standard of
measurement.
Unsaturated
Latin
un- not
-satur- full
Containing less of a solute required for equilibrium.

Uvula 193
Uracil
Latin
urina- (ur)ea urine
-acetum- (ac)ectic acetic acid, vinegar
-il substance relating to
An essential chemical of RNA.
Urease
Latin
urea- urine
-ase enzyme
An enzyme that promotes the hydrolysis of urea.
Ureter
Greek
ouron- water, rain, wet; urine
-ter denoting the instrument
A thick-walled tube that conveys urine from the
kidney to the urinary bladder.
Urethra
Greek
ourethra urinate
A canal extending from the bladder to the exterior
of the body; it carries urine in both sexes and
semen in males of the species.
Urinary
Greek
ouron- water, rain, wet; urine
Of or relating to the organs involved in the forma-
tion and excretion of urine.
Uropod
Greek
uro- tail
-pod foot
One of the abdominal appendages of a crusta-
cean, which are used chiefly in locomotion.
Uterine
Latin
uterus- womb
Of, pertaining to, or in the region of the uterus.
Uterus
Latin
uterus womb
A hollow muscular organ of the female mammal for
the gestation of fetuses, located in the pelvic region.
Utilization
Latin
utilize- to use
The act or process of putting something to use for
a productive purpose.
Uvula
Latin
uva- grape (swollen)
-ula little, small
A small, pendant/grape-shaped, fleshy mass of
tissue suspended from the center of the posterior
border of the soft palate.

Vaccine
Latin
vacc- cow
A substance prepared from pathogens that is
injected into the body in order to build antibodies
and create immunity from diseases caused by
those pathogens.
Vacuole
Latin/French
vacuus- empty
-ole little
A membrane-enclosed cavity that contains water,
food, or wastes from cellular activity.
Vagina
Latin
vagina sheath
A tube or canal that extends from the uterus to the
exterior of the body.
Valence
Latin
valere to be strong
Any number given to an element or ion as an indi-
cator of combining sites; also used to determine
whether electrons will be gained or lost as a result
of a chemical reaction.
Vapor
Latin
vapor diffuse matter in air
Suspended liquid, particulate matter, or smoke
within a gas, such as steam or fog.
Vaporization
Latin
vapor- diffuse matter in air
The process of converting a liquid into a gas.
Vaporize
Latin
vapor- diffuse matter in air
To convert or be converted into vapor.
Variation
Latin
variare- different, diversity, change
Divergence in the characteristics of an organism
from the species or population norm or average.
Varicose
Latin
varic- swollen vein
-ose full of, containing, having the qualities of,
like
Describes the abnormal condition of swollen or
twisted superficial veins.
Variegation
Latin
varius- various
-agere- to do, drive
Irregular variation in the color of plant organs,
such as leaves or flowers.

Venule 195
Vas deferens
Latin
vas- vessel, duct
-de- reverse the action of, undo, from, apart, away
-ferre to carry
The duct or tubule by which semen is carried
from the epididymis to the ejaculatory duct.
Vascular
Latin
vas- vessel, duct
-cul- small, tiny
Characterized by containing vessels that carry or
circulate fluids through plants and animals.
Vasodilation
Latin
vas- vessel, duct
-di- apart, away, from
-latus- wide
The act or process of increasing the diameter of a
small blood vessel.
Vasopressin
Latin
vas- vessel, duct
-premere- to press, curtail, prohibit
Antidiuretic hormone (ADH) secreted by the
anterior lobe of the pituitary gland. This hormone
simultaneously constricts small blood vessels,
raises blood pressure, and reduces urinary output.
Vasospasm
Latin/Greek
vas- vessel, duct
-spasmos involuntary contraction, pull
Constriction of a blood vessel.
Vastus
Latin
vastus broad, large
Term suggesting “large” or “broad,” in reference
to muscle size.
Vector
Latin
vehere to carry
In physics, a quantity with both magnitude and
direction. In biology, an organism that carries
pathological organisms and delivers them from
one host to another. In genetics, a plasmid or
other agent that carries genetic material from one
cell to another.
Vegetation
Latin
vegetat- to enliven
The act or process of vegetating; plants growing
in a given area.
Vein
Latin
vena vessel, tube
Large blood vessel that conducts blood toward
the heart.
Velocity
Latin
velox- quick
The vector quantity used to measure speed.
Vena cava
Latin
vena- vein
-cava empty, hollow
Very large veins, both superior and inferior, that
empty blood into the right atrium of the heart.
Vent
Latin
ventus wind
The opening of a volcano in the earth’s crust.
Ventifact
Latin
ventus- wind
-(arti)fact product or result
A stone that has been shaped by wind-driven sand.
Ventral
Latin
venter- belly
or character of
Of or close to the abdomen, on the front of the
human body or on the lower side of an animal or
fish.
Ventricle
Latin
ventricul- belly
-us thing
One of the small chambers or cavities usually
associated with the heart or brain.
Venule
Latin
vena- vessel, tube
-ule little, small
Smaller blood vessel that conducts blood toward a
larger vein that ultimately returns blood to the heart.

196 Vermiculite
Vermiculite
Latin
vermis- worm
-lithos- stone, rock
Any of a group of micaceous hydrated silicate
minerals related to the chlorites and used in heat-
expanded form as insulation and as a planting
medium.
Vermiform
Latin
verm- worm
A legless, wormlike larva without a well-developed
head.
Vertebrate
Latin
vertebratus- jointed
Having a backbone or spinal column; an animal
in the phylum Chordata, subdivision Vertebrata.
Vertex
Latin
vertere to turn
The point at which the sides of an angle intersect;
the highest peak of a mountain.
Vertical
Latin
vertic- highest point
or character of
The axis perpendicular to the horizon (up and
down); positioned at the highest point.
Vertigo
Latin
vertere to turn
The sensation of a whirling or spinning motion
associated with oneself or with external objects;
confused or disoriented.
Vesicle
Latin
vesic- little bladder
-ula little, small
Within the cytoplasm of cells, one of a variety of
small, membrane-bound sacs that function in the
transport, storage, or digestion of substances or in
some other activity.
Vestigial
Latin
vestigium- no sign of any return
Refers to an indication, either by structural feature
or some other minute piece of evidence, of the
existence of a body part that no longer is present in
the modern species (i.e., the forelimbs of ostriches).
Vibration
Latin
vibrare- to move back and forth
The act or process of rapidly moving back and forth.
Vibrissae
Latin
vibro- to quiver, to oscillate
-ae plural
Stiff hairs or feathers, usually projecting from the
face (i.e., whiskers).
Villus
Latin
vill- tuft of hair or fleece
-us thing
Small, fingerlike projections extending into the
interior of the small intestine and increasing the
absorptive area of the intestinal wall.
Viper
Latin
vipera snake
Any of several venomous Old World snakes of
the family Viperidae, having a single pair of long,
hollow fangs and a thick, heavy body.
Viremia
Latin
virus- poison
the blood
Viruses found moving within the bloodstream;
they may be pathogenic.
Virus
Latin
virus poison
Any of various simple submicroscopic parasites
of plants, animals, and bacteria that often cause
disease.
Visceral
Latin
viscidus- sticky
or character of
Of the internal organs of the body, such as the
heart, lungs, and intestines.
Viscosity
Latin
viscosus- sticky

Vulva 197
Numerical measure of the degree to which a fluid
resists flow under an applied force.
Vision
Latin
videre- to see
Eyesight; the ability to see.
Vitamin
Latin
vita- live
-ammonia- a colorless pungent gas, NH3
Various water- or oil-soluble organic substances
that are ingested in small amounts and are essen-
tial for growth and development.
Vitreous
Latin
vitrium- glass
Of or resembling glass; clear substance.
Viviparity
Latin
viva- life, alive
-para- to bring forth, to bear
Reproduction in animals whose embryos develop
within the female parent and derive nourishment
from her tissues (i.e., the placenta).
Volatile
Latin
volare- to fly
Refers to that which readily evaporates at room
temperature and pressure.
Volcanic
Latin
vol’nus- fire, flames (named after the Roman god
of fire)
Pertains to extrusive rocks that cool above the
surface.
Volcano
Latin
vol’nus fire, flames (named after the Roman god
of fire)
A mountain formed of lava, ash, and larger frag-
ments ejected during numerous eruptions.
Volume
Latin
volumen to roll
The amount of space occupied by a three-dimen-
sional object or region of space, expressed in
cubic units.
Volvox
Latin
volvere to roll
Hollow, spherical, multicellular green algae of
the genus Volox that are found in freshwater.
Vulva
Latin
vulva womb, covering
The external genitalia of the female, including the
labia, hymen, perineum, and clitoris.

Water
Old English
wæter water
Odorless, colorless, tasteless fluid vital to all
plants and animals.
Wattle
Old English
watel hurdle
A fleshy, wrinkled, often brightly colored process
hanging from the neck or throat, common in cer-
tain birds, such as chickens.
Wax
Old English
weax wax
Oils and greases composed of hydrocarbons and
esters that are quite sensitive to heat and insoluble
in water.
Weather
Old English
weder weather
The regional condition of the atmosphere with
respect to temperature, humidity, precipitation,
and wind.
Weight
Old English
wegan to weigh
The force on an object as a result of gravitation.
Work
Greek
ergon activity
The amount of energy required to exert a force
over a given distance.
Henry Cavendish
Perhaps Henry Cavendish lost his chance at fame
and glory because of his odd, quirky personality.
Henry was painfully shy toward strangers and
women. He was, however, respected and admired
by his colleagues. According to accounts from his
contemporaries, Henry would refrain from making
eye contact with anyone but those closest to him.
Henry Cavendish was born in Nice, France, on
October 10, 1731, and he died 78 years later, on
February 24, 1810. During his sequestered life,
Henry discovered some of the most important prin-
ciples of chemistry but historically has been given
little credit for those discoveries. After his death,
many of Cavendish’s discoveries were later made
by others. It wasn’t until James Clerk Maxwell, a
Scottish mathematician, went through Cavendish’s
writings in the latter part of the nineteenth century
that the outside world realized what Henry had
accomplished in his life. Ohm’s law, Dalton’s law
of partial pressure, and Charles’ law of gases,
though not so named, were among the principles of
chemistry included in Cavendish’s narratives.

Work 199
By experimentation, Cavendish was able to
accurately calculate the density of the earth relative
to water. The results of his experiments led to the
calculation of the actual mass of the earth. He was
accurate to within 1 percent of the earth’s actual
mass, which is estimated at 5.9725 billion trillion
tons.
We associate Henry Cavendish with the
discovery of the composition of water. Cavendish is
given credit for the discovery of hydrogen,
although, again, he didn’t name it as such. That did
not happen until Antoine Lavoisier researched
Cavendish’s experiments in 1777 and carried on
with them.
Henry Cavendish’s experiments with gases were
meticulously conducted. He repeated his trials with
gases over and over as he attempted to successfully
differentiate them by their specific gravity.
Cavendish accurately established the
composition of earth’s atmosphere as being 79.167
percent “phlogisticated” (inflammable) air and
20.8333 percent “dephlogisticated” air. Today we
know that most of the phlogisticated air is nitrogen
and the dephlogisticated air is oxygen.
dephlogisticated air + inflammable air →water
[Now: 2 H2 (g) + O2 (g) →H2O (l)]

Xanthic
Greek
xanthos- yellow
In botany, pertains to any plant or fruit that has a
tendency to be yellowish in color.
Xanthophyll
Greek
xenos- stranger, different
-phyll leaf
Yellow pigment that is found in the leaves of
green plants and is masked by the green pigment
chlorophyll.
Xenobiotic
Greek
xeno- guest
Pertains to a drug or other foreign substance
capable of harming another living thing.
Xenocrystal
Greek
-krustallos ice
A crystal foreign to the igneous rock in which it
occurs.
Xenogenic
Greek
Refers to a trait originating from a genetically dif-
ferent species and introduced into an organism.
Xenotransplantation
Greek/Latin
-trans- across or through
-plantare- to plant
The surgical removal of an organ or tissue from
one species and the transplantation of it into a
member of a different species.
Xerophyte
Greek
xeros- dry, arid
-phyte plant
A plant that lives in dry ecosystems, such as deserts.
Xiphoid
Greek
xiphos- sword
Refers to the pointed, cartilaginous tip attached to
the lower end of the breastbone or sternum; the
smallest and lowest division of the sternum.
Xylem
Greek
xulon wood
The supporting and water-conducting tissue of
vascular plants, consisting primarily of woody
tissue.
Xylophage
Greek
xulon- wood
-phage eat, eating, consume, ingest
An organism that eats wood, typically an insect.
Certain mollusks and fungi also bore into wood.

Yeast
Old English
gist yeast
Single-celled fungi belonging to the families
Ascomycetes and Basidiomycetes.
Yew
Old English
iw yew
A type of evergreen tree found mostly in temper-
ate climates and thriving in acid soils.
Yield
Old English
gelda to pay
In biology, the amount of food gathered from a
given crop. In chemistry, the amount of product
obtained from a given chemical reaction.
Yolk
Old English
geolu yellow
The yellow substance of an egg, composed of
water, protein, and lipids, that is surrounded by a
clear, proteinatous layer of albumen.
Youze
East India
youze cheetah
The cheetah.

Zeatin
Greek
zeia- wheat, barley, corn
A plant hormone found in the endosperm of maize
fruits.
Zein
Greek
zeia wheat, barley, corn
A protein found in corn that is used in plastics,
coatings, and adhesives
Zenith
Latin/Arabic
semita path over the head
The point on the celestial sphere that is directly
above the observer.
Zeolite
Greek
zein- to boil
-lithos rock, stone
Aluminum silicate mineral whose molecules
enclose cations of sodium, potassium, calcium,
strontium, or barium; used chiefly as molecular
filters and ion-exchange agents.
Zero
Arabic
sifr nothing, cipher
Empty, nothing; the absence of any integer.
Zinc
Old German
zinko spiked (because it became spiked or jagged
in the oven)
A metal that is whitish in color and malleable at
warm temperatures; one of a group of metals used
in the making of alloys.
Zircon
Persian
zargun- (Persian form zarg n) gold colored
c- (as in çiy diya) fire worship month
-g n color
Stable mineral found in granite and that provides
evidence for the earth’s crust being at least 4.2
billion years old; a brown to colorless mineral,
ZrSiO4, which is heated, cut, and polished to
form a brilliant, blue white gem.
Zoanthropy
Greek
zoon- animal, animal-like
-anthropo- man; human being, mankind
A mental disorder categorized as a monomania,
where an individual believes he has transformed
himself into another animal.
Zone
Greek
zone girdle, celestial zone
A distinctive region or area that is characterized
by a common set of features and relatively dis-
tinct boundaries.
Zoobenthos
Greek
of the sea
Those fauna living in or on the seabed or lake floor.
a u
a a a
u

Zygodactylous 203
Zoodomatia
Greek
-domatia commune, home
Plant structures that act as shelters for animals.
Zooflagellates
-flagell- a whip
A group of animal-like protists that are character-
ized by having flagella.
Zoology
Greek
bodies of knowledge
The branch of biology that deals with the study of
the structure, physiology, development, and clas-
sification of animals.
Zoonosis
Greek
-noso- disease
Any infection of a human by a pathogen whose
source is a reservoir of a nonhuman animal
pathogen.
Zooparasite
Greek
-para- beside; near; alongside
-sitos- grain, food
-ite resident
An animal that feeds off a host organism.
Zoophagous
Greek
A broad term applied to animals that feed off
other animals.
Zoophyte
Greek
-phyte a plant
Any animal that resembles a plant more than an
animal in morphology or mode of life.
Zooplankton
Greek
-planktos- passively drifting, wandering, roaming
-on a particle
Small animals that float or swim near the surface
of water.
Zooplasty
Greek
The surgical procedure whereby animal tissue is
grafted and implanted in humans.
Zoosmosis
Greek
-osmos- for thrust, push
The osmotic process occurring in living systems,
specifically in animals.
Zoosporangium
Greek
-spora- seed
A vesicle in plants that holds zoospores.
Zoospore
Greek
-spora seed
Spores possessing flagella that are capable of
locomotion.
Zootoxin
Greek
-toxicum poison
A poison produced by an animal.
Zooxanthella
Greek
-xanthos- yellow
-ella dimunitive
Microscopic yellow-green algae that live symbi-
otically within the cells of coral.
Zwitterion
German
zwitterion hybrid ion
A molecule that has positive and negative charges
on opposite sides; a dipolar molecule.
Zygodactylous
Greek
zugon- to yoke, pair
-daktulos- toe, finger, digit
A term applied to yoke-toed birds such as wood-
peckers, parrots, and cuckoos; the toes of these

204 Zygoma
birds are in sets of two, with one set lying anterior
to the leg and the other posterior.
Zygoma
Greek
zugoun to join, bolt
The slender bony arch that joins the cheek to the
temporal bone.
Zygomatic
Greek
zugoun- to join, bolt
Of or relating to the area of the zygoma.
Zygomorphic
Greek
Refers to an organism having a paired or bilateral
symmetry.
Zygospore
Greek
-spora seed, a sowing
A thick-walled spore of some algae and fungi
formed by the union of two similar sexual cells;
usually serves as a resting spore and produces the
sporophytic phase of the plant.
Zygote
Greek
zugon to yoke, pair
A cell formed by the union of two gametes.
Zymurgy
Greek
zym- leaven
-ourgos work
The branch of chemistry that deals with the pro-
cess of fermentation.

Common Prefixes
ab- off, away from
acere- to be sour
algeis- pain
alkali- (Latin) basic, pH more than 7
word al-qali, which means “ashes,” and recalls the
elements Na [sodium] and K [potassium] left in
the ashes of burning wood or plants)
ana- anew, up
andros- male
anemos- wind
aqua- water
art ri - windpipe, artery
arthr- joint
astros- star
athera- tumors full of pus, like a gruel
atmos- vapor
atri- open area, central court, hall, entrance, or main
room of an ancient Roman house
avis- bird
baktron- a staff; rod
“pressure”
bathy- deep, depth
blastos- germ, bud
brakh n- upper arm
bronkhos- windpipe
centi- one hundredth
chaeto- spine, bristle; long, flowing hair
cheil- claw, lip, edge, or brim
chemo-, khemeia- chemical/alchemy
co- to the same extent, degree; together, jointly
com- (con) together, with, jointly; compress, converge
dactylo- finger, toe
deinos- terrible, monstrous
dermat- skin
di- apart, away, from, two
diploos- double
dis- apart, away from, utterly, completely, in all
directions
dys- painful, difficult, disordered, impaired, defective, ill
e- out
ektos- outer; external, out of, out, outside; away from
e a
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206 Common Prefixes
lektron- charge, electricity, dealing with positive
environ- round about; encircle
ex- outside/outward, out of, out; away from
ferrum- iron; pertaining to or containing iron
structure
frangere- to break
ge- earth, world
gen- origin, birth
germen- a bud, offshoot
haima- blood
h lio- sun
hemi- half
hepta- liver
heteros- different
homeo- same, like, resembling, sharing, similar, equal
hyper- above, high
deficient
inter- among, mutually, together, between, among
kard- heart, pertaining to the heart
khromat- color
klinein- to lean, sloping
kyklos- circle, wheel, cycle, rotate
lipos- fat
magn- great
mala- bad
medius- middle
megas- large, great, big, powerful
melas- (melas) the color black, dark
mesos- middle
micro- denotes one-millionth of a part
morph- shape, form, figure or appearance
myco- fungus
myo- muscle
necro- death
nephros- kidney
neur- nerve, cord
nom- (nemein) to dictate the laws of, knowledge,
usage, order
non- not, lack of
oikos- home, house
oion- egg
or- mouth
s- mouth
osteon- bone
ovum- egg
pan- all
para- beside, near, alongside
ped- foot
phainein- to show, appear, display; making evident;
literally, “to come”
pherbein- to graze
pherein- to carry, bear, support; go
philos- love, fondness for, loving
phukos- rock lichen, seaweed
phullon- leaf
phuton- plant
pinein- to drink
plastos- (plassein) something molded; to mold
platus- flat
poly- many or much
pro-, prot- before, forward; for, in favor of; in front of
proteros- earlier
pseudes- false
pteron- feather, wing
quadi- four
radi- radiant or radiation energy, wireless transmitter
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Common Prefixes 207
re- to do something again or go against
rodere- to gnaw
sapro- rotten, putrid, decay
sed- sit
semi- half
s pein- to make rotten, putrefactive
sinus- hollow
sklero- hard
spora- seed
staphylo- cluster
stereos- three dimensional, solid, firm, hard
layer, cloud layer
sub- under or below
sym- with, together
syn- joined together, together with
telos- end
topos- place
tri- three
stimulus
trophos- (trophein) to nourish, food, nutrition;
development
ultra- beyond, to an extreme degree
un- not
uni- same, one
vas- vessel, duct
vena- vein
viva- life, alive
e

Common Roots
abdomen belly, venter
aberrare deviation from the proper or expected course
abradere to scrape off
accipiter hawk
accuratus done with care
acere to be sour
acerv re to heap
activus to drive, do
ctus to set in motion
acus (acuere) to sharpen; needle, point
aden lymph gland(s)
adip of or pertaining to fat
aera counters
aerobe organism requiring oxygen to live
aesthe feeling, sensation, perception
aestus tide, surge
agogos a leading, a guide
agon conflict, contest
agulum to condense, to drive
aion indefinitely long period of time
aisthesis feeling
aither upper air
aitia cause
akanthos thorn plant
aktin ray (as of light), radiance, radiating
albumo the color white
albus the color white
aleiphein to anoint with oil
alere to nourish
alescere to come together or grow
alga seaweed
algesi pain, sense of pain; painful, hurting
alimentum nourishment, supplying food
alkali (Latin) basic, pH more than 7
alkyl alcohol; a monovalent radical, such as ethyl or
propyl
alleion mutually
alligare to bind
allium onion, garlic bulb
alqili (Arabic) ashes (originally from Arabic word
al-qali, which means “ashes,” and recalls the ele-
ments Na [sodium] and K [potassium] left in the
ashes of burning wood or plants)
alter other
altus high, highest, tall, lofty
alveus hollow, belly
am (ampere) named for Andre Marie Ampere
amalgama mixture
ameibein to change
amino relating to an amine or other compound con-
taining an NH2 group
ammonia a colorless pungent gas, NH3
amnion embryo, bowl, lamb
ampho (amphoteros) both, each of two
amplus large, full
amygdale almond
analogos proportionate
ancon elbow
ane organic compound containing no multiple bonds
angeion vessel, usually a blood vessel
angulus angle
ankhon a strangling
annellus little ring
antara interior
anth flower, that which buds or sprouts
anthrankitis name of a fiery gem
anthropo man; human being, mankind
aort lower extremity of the windpipe; by exten-
sion, extremity of the heart, the great artery
apat deceit
aponeurousthai to become tendinous
aptare fit, fitted, suited
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210 Common Roots
aqua water
arakhn spider
arassein to strike
arbor tree
arc bow, arch, or bend
archae original, beginning, origin, ancient
argillos clay
arithmos number
aroma smell (due to sweet smell of benzene and
related organic groups)
arthr joint
articulus small joint
artificialis not natural, manmade
askarizein to jump, throb
askos bag
astros star
äther etherlike acid
atri open area, central court, hall, entrance, or main
room of an ancient Roman house
audit hearing, listening, perception of sounds
augere to increase
auricula ear
aurora dawn
aurum gold
austr south, south wind
auxein to grow
avis bird
awariyah damaged merchandise
axios worthy
axis central
ax n axis
baktron a staff; rod
bar weight, pressure
basid foundation or base
basis fundamental ingredient, foundation
benthos deep; the fauna and flora of the bottom of
the sea
beta second letter of the Greek alphabet
bio life, living organisms, or tissue
bios life, living organisms, or tissue
bit men a mineral pitch from the Near East
blaedre bladder
blastos bud, germ cell
blepharon eyelid
bl d to thrive or bloom
bol (ballein) to put or throw
bombos booming sound
boreios coming from the north
botah (body) the material frame of humans and animals
botan fodder, plants
botulus sausage
bov cow
brakh n upper arm
bredan to breed
bresta to break asunder
brevis brief
bronkhos windpipe
bruein to be full, bursting
bruon moss
bul place for
bulla bubble
buoy to float
bussos bottom
bustus to burn
cadere to fall, die
caecus blind
caelum sky, heaven
caldaria cooking pot
calor heat
calve calf
cambiare to exchange
camoufler to disguise
can lis conduit
cancer crab
candela candle
cani dog
canthus rim of a wheel or vessel
cap catch, seize, take hold of, contain, take, hold
capacitas spacious
capill hairy
cappa cap or cape
carbo coal, charcoal
carbonate to charge with carbon dioxide gas
carota carrot
carpus wrist; that which turns
cartilago cartilage
caud tail
caudex book
caulis stem
cauter heat
cavare to make hollow
c dere to go
cella chamber
cellula little cell
centrum center
cephalo (kephalikos) head
cer wax
cerebr of or relating to the brain or cerebrum
cernre to separate
c russa a white lead pigment, sometimes used in
cosmetics
cervic stem of cervix
cetu whale
chemo, khemeia chemical; alchemy
chimaira she-goat
chir hand; pertaining to the hand or hands
chore a central and often foundational part, usually
distinct from the enveloping part by a difference in
nature
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Common Roots 211
chylos juice
ciere to set in motion
circulus to make circular
circum in a circle; around, about, surrounding
cirro hair or wispy
cist to cut
cl vis key (from its shape)
cleave to split or separate
clitellae packsaddle
cloa’cae drain
clupea herring, small fish
co gulum coagulator
cod a code of laws, a writing tablet; an account book
coelom, (koilomat) cavity
colere to till
commodus to adjust, suitable
communis commons
compose to form, create
conch shell
copula bond or pair
corneus horny
corniculum horn, hornlike structure
corolla small garland
corona crown
cortic bark, rind, that which is stripped off
costo rib
cracian to break apart
cremo, crem to hang; hung, hung up
creper dark
creta chalk
crevace crevice
cropp craw
crum planted with trees
crusta shell, hard surface of a body
cult to care for, to dwell, to inhabit
cumaru tonka bean tree
cumul pile or heap
cumul re to pile up
currere to coincide
cuspis sharp point, cusp
cutis skin
cutten to separate into parts with or as if with a
sharp-edged instrument
cyano (kyanos) blue, dark blue
cygnus swan
cyte (kutos) sac or bladder that contains fluid
daktulos toe, finger, digit
datum something given
decidu to fall off
degrade to impair physical structure
dei god, deity, divine nature
deletes to erase, destroy
deliquiscere melt by absorption of moisture
delo visible, clear, clearly seen; obvious
demos population, people
dendr tree, resembling a tree
dens to press close together
densi thick, thickly set, crowded, compact
denti teeth or tooth
dentis tooth
derm skin
desiccare make quite dry
deterere to lessen, wear away
deuteros second, two in number
diast dilation, spreading
dicho akin to
didumos twins, testicles
diffundere to spread out
digerere to break down
diploos double
diurnus day
diverse differing from another
dold to dull
dominae to rule
domo house, home
doopen to dip
dormire to sleep
dorsalis back
draga to draw, drag
dramein/dromos to run
drum ridge, back; long, narrow hill
ducere to lead, bring, take; to draw or lead
ductus to be hammered out into a tube or pipe;
leading or drawing
dunamikos powerful
duodecum twelve
durare to harden; hard growth
dygre dry
eco environment, habitat
efficere to effect
eghe resembling an eye shape
eicere to throw out
eisodios coming in besides, entering
ekdusis to shed or molt
ekithos yolk
elaunein to beat out
lektron charge, electricity, dealing with positive
elementum rudiment, first principle
eliminat to banish
elleiptikos of a leaf shape; in the form of an ellipse
elongate to make or grow longer
elutron sheath
mittere to send out
empeirikos doctor relying on experience alone
enchyma tissue
enkephalos in the head
enteron intestine
entomos cut from two, segmented
equus horse
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212 Common Roots
erbe herb
erem lonely, solitary; hermit; desert
ergon work
erosio an eating away
estiv dormancy in the summer
etymon true sense; earlier form of a word
eurus a widening; broad, wide
evolut unrolling
experiri to try
externus outward
facere to do, carry, bear, bring
fecere make, do, cause, produce, build
ferre to carry
fibre an elongated, threadlike structure
flagrum whip
fl oge fly
florere flower; to blossom
focus (fuel) hearth, fireplace
folium leaf
foris outside
formyl: form(ic) found in ants or relating to ants +
-yl suffix for organic acid
frangere to break
fugere to flee
fungi performance, execution
furca a fork
gaia earth
gastr stomach, belly
ge earth, world
gen to give birth, kind, produce
genitus born, to bear
gerere to bear
glene eyeball
glotta tongue
glutinare to glue
gl t re to gulp
gnatha jaw
gn to come to known
gnose to know or learn
gonos offspring
gradus step or degree
gradus walk, step, take steps, move around; walk-
ing or stepping
gramma letter
graphia (graphein) to write, record, draw, describe
gynous in relation to a female organ of a plant
haerere to stick together, cling to
haima blood
hal salt
havour to have
hedron face
helios sun
heteros different
histanai to place, to stop
homolus even
hormo to rouse or to set in motion
hudor water
hybrida mongrel offspring
hydr water
jugare to join together
kainos recent
kairon nut; cell nucleus
kalendae account book
kalyx cup
kapnos smoke, carbon dioxide (CO2 )
kard heart, pertaining to the heart
karkinos crab, cancer
karoun to put to sleep, plunge into sleep or stupor,
stupefy
karpos fruit
kata down, downward; under, lower; against;
kele hernia, tumor
kentein to prick, puncture
kentron center, sharp point
keras horn
kerkos tail
khartes map, chart, paper
kheilos lip
khole bile
khorde gut, string of a musical instrument
khorion afterbirth
khr ma color
khronos time
khr sallid gold-colored pupa of a butterfly
khumos juice
kin’ dh to sting, nettle
kine movement, motion
kinein to move
kirkos circle
kirrhos tawny yellow
klados branch or spout
klastos break, break in pieces
kleitoris clitoris
kleps to steal
klime slope
klinein to lean, sloping
klinikos pertaining to a bed or couch
klisis inclination
kl n young shoot or twig
kn kos safflower
koiloma cavity
kokhlias snail
kokkos berry, grain, seed
kolkhikon meadow saffron
kolla glue
kolon large intestine
kometes long-haired
koneion poison hemlock
konis dust
e
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Common Roots 213
kope oar
kosmos universe, order
kotuledon a kind of plant, a seed leaf, a hollow or
cup-shaped object
kranion skull
krater bowl for mixing wine and water
kreat flesh
krinein to separate
kroke pebble
krustallos ice, crystal, freeze, icelike
kuhl essences obtained by distillation
kustis (cyst) sac or bladder that contains fluid
kyklos circle, wheel, cycle, rotate
lapar the soft part of the body between the ribs, hip,
and flank; the loin
l tus wide
legein word, speech
leipein to leave
lekithos egg yolk
libr balanced, level; make even; weight
lig re to tie, bind
ligo bind, tie
lipo abandon, to leave (behind)
lite (lith) stone or rock
locare to place
luere to wash, clean
lunar moon, light, shine
ly (luein) to loosen, dissolve, dissolution, break
magnes figurative sense of something that attracts
malacia softening of tissue
malgama soft mass
m ter mother
maza mass, large, amount
mbolon wedge, peg
megas large, big, great
melas black
mensa table
meros part
meta later in time
metallon mine, ore, quarry; any of a category of
meter (metron) instrument or means of measuring;
to measure
(meth)ane an odorless, colorless gas, CH4
metiri to measure out
metra womb
metria (metron) the process of measuring
migrare to move
miktos mixed or blended
minie mimic, mime; imitate, act; simulation
mittere to put
mixis mingling, intercourse
morph shape, form, figure, or appearance
morpheus god of dreams
muk s fungus
mulg re to milk out
myo muscle
nasus nose
nautes sailor
necro death
negare say no, to deny
nekros death, corpse
nephros kidneys
neur nerve
nervus sinew, tendon
nimbus cloud
noct night
nom (nemein) to dictate the laws of, knowledge,
usage, order
nosia disease
och fixed
ocul of or relating to the eye
odontos tooth
oid ma a swelling
oikos home, house
optic eye, optic
orexis appetite
otic state or condition of; condition of being
oxo oxygen
oxus sharp
oxy pungent, sharp
parare to make ready
particula a very small piece or part; a tiny portion
or speck
pathos feeling, sensation, perception; suffering,
disease
pectin comb
ped foot
pendere to hang
peps digestion
pestis (Latin) plague, pestilance
petere to strive
phage to eat
phagei to eat
phagos (phagein) to eat, eating
phana speech
pharynx throat
phase a stage
phatos speech, spoken
phile one who loves or has a strong affinity or pref-
erence for
phonos voice
phore bearer, carrier
phoreus bearer
phoros being carried, bearing
photos light, radiant energy
phragma fence
phren diaphragm, midriff, heart
phuein to grow
phullon leaf
a
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214 Common Roots
phusan to blow
phusis nature
phuton plant having a (specified) characteristic or
habitat
phyein to grow
phyte plant
pithecus ape, apelike creatures
plasm (plassein) to mold or form cells or tissues
plassein to form
plastos (plassein) something molded (to mold)
plexus an embrace
pnea breathing or breath
pneumon wind, breath
pnion breathing or breath
pod foot
poiein production, formation; to make
pole either of two oppositely charged terminals
pollere to be powerful
ponere to put together
potent power; to be able
praktikos practical
premere to press
proktos anus
pteron feather, wing
ptilon plume
p r fire
pyge rump or buttocks
pyle gate
qalib shoemaker’s last
ramus branch
reciepere to receive
ren the kidneys
rhein to flow or run
riche rich
rigare to wrinkle
rocca rock, stone
rota wheel
rube red
saccharon sugar
safira to be empty
sauros lizard
scire to know
scoli curvature, curved, twisted, crooked
sectus to cut
seminare to plant or propagate (from semen, semi-
nis meaning “seed”)
sent re to feel
sepein to decay, cause to rot
sepsis putrefaction or decay
ser the watery part of fluid
servare to preserve
sexus sex
sicca drying
simulare to make similar or alike
skeletos dried body
sklero (skl roun) to harden
skopein see, view, sight, look at, examine
sociar to join
solvere to loosen
soma (somatiko) body
sorbere to suck
spargere to scatter or strew; sprinkle
sperma seed
sphaira a globe shape, ball, sphere
sphyzein to throb; pulse, heartbeat
spir breath of life, breath, breathing
spora seed
stare to stand firm
statos standing, stay, make firm, fixed, balanced
stele pillar
stella star
stereos solid, being of three dimensions
sthenos strength
stigma a point, mark, spot, puncture
stillare to drip or trickle
stingere to pull
stinguere to quench
stipare to press together
stoma mouth
sumere to take
summetros of like measure
sumptotos intersecting
sustellein to contract
sylos a pillar
systema the universe
taktos ordered
taxi arrangement, order; put in order
teg touch, reach, handle
tekhne skill, systematic treatment
temnein to cut
ten to move in a certain direction; to stretch, hold
out
tenere to hold together
tenuis thin
terr re to frighten
thalpien to heat
thele nipple
therapeuein heal, cure; treatment
thermos combining form of “hot” (heat)
thorax breastplate, chest
tomos (temnein) to cut, incise, section
tonos tone, stretching, firm
topos place, spot
torn re to round off
toxikos poison
trahere to draw
tribuere to give
tripsis a rubbing (so named by its first being
obtained by rubbing a pancreas with glycerin)
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Common Roots 215
trope bend, curve, turn, a turning; response to
stimulus
trophos (trophein) to nourish, food, nutrition;
development
trudere thrust
tundere to beat
tupos type, model, stamp
unus one
vacare empty
vagina sheath
valere to be strong
valve leaf of a door
vaporatus steam, vapor
variare to vary
vascul small vessel
vehere to carry
vent come
ventricul belly
verge to tend to move in a particular direction
vertere to turn, turn around
vextus to be vaulted
vorare to devour
vore eat, consume, ingest, devour
weike pliant
zein to boil
zoe life
zoon animal, animal-like
zuma leaven, yeast

Common Suffixes
-able/-ible capable of
-ac pertaining to
-ad member of a botanical group
-ae plural
-al of the kind of, pertaining to, having the form or
character of
-ance brilliance, appearance, state, quality
-ancy condition of or state of
-androus man, men, male, masculine
-angeion diminutive of “vessel”
-ant having the quality of
-ase enzyme
-ate an organism having these characteristics; charac-
terized by having; a derivative of a specific chemi-
cal compound or element
-baros weight, heavy, atmospheric pressure
-benthos deep; the fauna and flora of the bottom of
the sea
-cephaly (kephalikos) head
-chrome pigment
-dactylos finger, toe
-derm skin
-dynia pain
-ectasis expansion, dilation
-ekt outside, external, beyond
-ella little, dimunitive
-emesis vomit
-emia the condition of having (a specific thing) in the
blood
-en to make or cause
-ent causing an action, being in a specific state, within
-ferre to carry
-ferrous bear, carry; produce
-fy (ficare) cause, to become; make, do, build, produce
-genus offspring, kind
-geny birth, descent, origin, creation, inception,
beginning, race, sort, kind, class
-gram something written or drawn; a record
-haima blood
-haptien to fasten, join
-ia names of diseases, place names, Latinizing plurals
-ide binary compound; group of related chemical
compounds; nonmetal radical
-ify (ficus) make, or cause to become
-il substance relating to
-in protein or derived from a protein; neutral chemical
-ine of or relating to; a chemical substance
-inferus below, low
-ion (ienai) to go, something that goes
a

218 Common Suffixes
-ious full of, having the quality of, relating to
-ite minerals and fossils; component of a part of a
body; a part of or product of
-ium quality or relationship; chemical element
-ive performing or tending toward a specific action
-lite combining form used in naming of minerals
-lithos stone or rock
-logic talk, speak; speech, word
-logist one who speaks in a certain manner; one who
deals with a certain topic
-logos word, proportion
-logy (logos) used in the names of sciences or bodies
of knowledge
-lus thing
-lympha clear water, water nymph
-lyte substance capable of undergoing decomposition
-mania obsessive preoccupation with something;
madness, frenzy; obsession or abnormal desire for
-megaly large
-ment state or condition resulting from a (specified)
action
-meter (metron) instrument or means of measuring;
to measure
-nom (nemein) to dictate the laws of, knowledge,
usage, order
-nosis disease
-odont having teeth
-ol alcohol, chemical derivative
-ole little one
-oma tumor, neoplasm, community
-on a particle
-opsy examination
-or a condition or property of things or persons, per-
son that does something
-ory tending to, serving for
-osis disease or abnormal condition
-pherein to carry
-phile one who loves or has a strong affinity or pref-
erence for
-phobos fear
-phyte plant
-plasia (plassein) something molded (to mold)
-plasy growth or development of
-ploid having a number of chromosomes that has
specified relationship to the basic number of
chromosomes
-pod, -poda, - podos, - pous foot
-pterux wing
-spora seed, a sowing
-statos standing, stay, make firm, fixed, balanced
-status to come to a stop, to stand
-stoma mouth, opening
-superus higher, upper
-tonia, -tone tension, pressure
-trope bend, curve, turn, a turning; response to stimulus
development
-ula diminutive, little, small
-us singular, thing
-zoan animal
e

Resources
The American Heritage Dictionary of the English Lan-
guage, 4th ed. New York: Houghton Mifflin, 2004.
The American Heritage Stedman’s Medical Dictionary.
New York: Houghton Mifflin, 2002.
Answers Corporation. Answers.com. Online encyclope-
dia, thesaurus, dictionary definitions, 2006.
Bartlett, John, comp. Familiar Quotations, 10th ed., rev.
enl. by Nathan Haskell Dole. Boston: Little, Brown,
1919; Bartleby.com, 2000.
Biology-Online.org. Biology Online—Information in
the Life Sciences, 2006.
Bragg, Melvyn. On Giants’ Shoulders: Great Scientists
and Their Discoveries from Archimedes to DNA.
London: Hodder & Stoughton, 1998.
Chabner, Davi-Ellen. The Language of Medicine, 3rd
ed. Philadelphia: W. B. Saunders, 1985.
Columbia University Press. The Columbia Electronic
Encyclopedia, 6th ed., 2003.
Dictionary of Latin and Greek Words Used in English
Vocabulary. Senior Scribe Publications, 2003 to
2006. http://www.wordinfo.info.
Gribbin, John. The Scientists. New York: Random
House, 2002.
Herron, W. B., and N. P. Palmer. Matter, Life, and
Energy. Chicago: Lyons & Carnahan, 1972.
Hurd, Charles, and Eleanor Hurd. A Treasury of Great
American Letters. New York: Hawthorn Books, 1961.
Knowles, Elizabeth. The Oxford Dictionary of Quota-
tions, 6th ed. Oxford: Oxford University Press, 2004.
Little, R. John, and C. Eugene Jones. A Dictionary of
Botany. New York: Van Nostrand Reinhold, 1980.
Merriam-Webster’s Collegiate Dictionary, 11th ed.
Springfield, MA: Merriam-Webster, Inc., 2006.
Palmer, E. Laurence, and H. Seymour Fowler. Fieldbook
of Natural History. New York: McGraw-Hill, 1975.
Peterson Field Guide to Rocks and Minerals. New York:
Houghton Mifflin, 1998.
Roget’s II: The New Thesaurus, 3rd ed. New York:
Houghton Mifflin, 1995.
Sagan, Carl. Broca’s Brain. New York: Random House,
1979.
Sagan, Carl. Cosmos. New York: Random House, 1980.
Schuster, M. Lincoln. A Treasury of the World’s Great
Letters. New York: Simon & Schuster, 1950.
Thompson, Ida. The Audubon Society Field Guide to
North American Fossils. New York: Alfred A.
Knopf, 1982.
Whitaker, John O., Jr. The Audubon Society Field Guide
to North American Mammals. New York: Alfred A.
Knopf, 1980.
Wikimedia Foundation. Wikipedia, the Free Encyclope-
dia. 2006. http://www.wikipedia.com.
WordNet 1.7.1. Princeton University, 2001.

About the Author
JOSEPH S. ELIAS is an Associate Professor of
Science Education at the Kutztown University of
Pennsylvania. He holds a BS in biology (Kutz-
town University, 1971), an MS in science educa-
tion (Temple University, 1976), and a doctorate in
science education (Temple University, 1989). He
has been teaching pre-service secondary educa-
tion science majors for over 14 years. He also is a
university supervisor of secondary education clin-
ical students and teacher interns. Dr. Elias teaches
in the graduate school at Kutztown University as
well. His graduate courses include methods of
research in biology and methods of teaching sci-
ence to middle and high school students. Prior to
teaching at Kutztown University, Dr. Elias taught
as an adjunct faculty member in the biology
departments of Cedar Crest College and Lehigh
Carbon Community College.

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