semantic-change

Semantic change is how a word's meaning drifts over time — the shift in what a community takes a term to mean as it passes from mouth to mouth, field to field, generation to generation.

The forces are many and named: metaphor (a word stretches to a new likeness), ellipsis (a phrase sheds a part and the remainder carries the whole), pejoration and amelioration (a word sinks or rises in feeling), specialization (a word narrows) and generalization (a word widens). Which force dominates depends on the speech community: a technical term in a young field (computer science) is pressed to generalize — it must cover more cases as the field grows — while a term in an old field (law) is pressed to specialize, narrowing to keep its precision. The mutation pressure on a definition — how fast it drifts, whether it is copied verbatim or rephrased — is a property of the field's communication needs, not of the word itself. This is why a coined term's first definition is a fingerprint that fades as the contribution grows: the definition mutates as it spreads, and the community that adopts it reshapes it to fit.