Semantics is the study of meanings of words, phrases, and sentences. It focuses on the conventional meanings of words rather than what a speaker intends. Conceptual meaning refers to the basic components of a word's meaning, like "thin sharp steel instrument" for the word "needle." Associative meaning involves connotations a word evokes, like "needle" suggesting pain. While linguists study conceptual meanings, poets and advertisers leverage associative meanings. Semantic features help account for sentences that are syntactically valid but semantically odd, like "The hamburger ate the man."