synonym

A word that has a closely similar meaning to another word. English has very few true synonyms (e.g. sofa / couch / settee), but many near synonyms, e.g. house - dwelling - home - abode - pad. The existence of synonyms allows variety of word choice according to style and register. A list of synonyms is available in a thesaurus. 

Compare antonym.

» Linguistic Library (Mike Green)