n. One word used to express distinct meanings, or applied as a name to different things: as, Heteropus is a homonym of eight different genera.n. In philology, a word which agrees with another in sound, and perhaps in spelling, but is not the same in meaning; a homophone: as, meet, meat, and mete, or the verb bear and the noun bear.n. Specifically, in systematic biology, a name given to a group (usually a genus or species) at a later date than that at which the same name had been given to another group.