- u|ni|on|id
- u|ni|on|id «YOO nee ON ihd», noun.any member of a large and widely distributed family of freshwater mollusks, especially numerous in the United States, whose developing larvae are parasitic on fish.╂[< New Latin Unionidae the family name < Latin ūniō, -ōnis a single large pearl; (originally) union]
Useful english dictionary. 2012.