Semantic change
（重定向自Ameliorative）
Semantic change (also semantic shift, semantic progression or semantic drift) is the evolution of word usage — usually to the point that the modern meaning is radically different from the original usage. In diachronic (or historical) linguistics, semantic change is a change in one of the meanings of a word. Every word has a variety of senses and connotations, which can be added, removed, or altered over time, often to the extent that cognates across space and time have very different meanings. The study of semantic change can be seen as part of etymology, onomasiology, semasiology, and semantics.