Definition of: synonym

(sin′ə·nim) noun
1. A word having the same or almost the same meaning as some other; hence, one of a number of words that have one or more meanings in common: opposite of antonym.
2. The equivalent of a word in another language.
3. Biol. A scientific name, as of a genus or species, superseded or discarded, as by the law of priority or because of incorrect application. Also syn′o·nyme. [<LL synonymum <Gk. synōnymon, neut. of synōnymes having like meaning or name <syn- together + onyma, onoma a name]
—syn′o·nym′ic or ·i·cal adjective
—syn′·o·nym′i·ty noun