"cognate word, a word which is derivative from another or from the same third word," 1846, from Greek paronymos, "formed by a slight change," from para- (see para- (1)) + onyma "name" (from PIE root *no-men- "name"). Paronymous "having the same derivation, allied in origin" is from 1660s; in the sense of "having similar sound but differing in spelling and sense" is is by 1836. Related: Paronymic; paronymy.