Definitions
1.noun(strictly) A word whose meaning is the same as that of another word.
2.nounA word or phrase with a meaning that is the same as, or very similar to, another word or phrase."“Happy” is a synonym of “glad”."
3.nounAny of the formal names for a taxon, including the valid name (i.e. the senior synonym).
4.nounAny name for a taxon, usually a validly published, formally accepted one, but often also an unpublished name.
5.nounAn alternative (often shorter) name defined for an object in a database.