Main Entry: syn·o·nym

Pronunciation: \ˈsi-nə-ˌnim\

Function: noun

Etymology: Middle English sinonyme, from Latin synonymum, from Greek synōnymon, from neuter of synōnymos synonymous, from syn- + onyma name — more at name

Date: 15th century

1 : one of two or more words or expressions of the same language that have the same or nearly the same meaning in some or all senses
2 a : a word or phrase that by association is held to embody something (as a concept or quality) <a tyrant whose name has become a synonym for oppression> b : metonym
3 : one of two or more scientific names used to designate the same taxonomic group — compare homonym

— syn·o·nym·ic \ˌsi-nə-ˈni-mik\ also syn·o·nym·i·cal \-mi-kəl\ adjective

— syn·o·nym·i·ty \-ˈni-mə-tē\ noun