Pronunciation: (mOOn'fish"),[key] —n., —pl.(esp. collectively)-fish,(esp. referring to two or more kinds or species)-fish•es. 1. Also called horsefish, horsehead. any of several silvery marine fishes of the genus Selene, having a very compressed body and inhabiting shallow coastal waters.
2. the opah.
3. any of various other rounded, silvery fishes.