This document provides an introduction to demand, including key terms and concepts:
1) Demand is defined as the willingness and ability to pay for a certain quantity of a good or service. Quantity demanded refers to the amount consumers are willing and able to purchase at a given price.
2) Ceteris paribus means "all else equal." The law of demand states that, ceteris paribus, quantity demanded increases as price decreases, and decreases as price increases.
3) Movement along a demand curve shows how quantity demanded changes with price, holding all other factors constant. Individual and market demand schedules illustrate the relationship between price and quantity demanded.