/ Dictionary / Index M moonfish: Meaning and Definition of Find definitions for: moon•fish Pronunciation: (mn'fish"), [key] — pl. -fish, -fish•es. Also calledany of several silvery marine fishes of the genus Selene, having a very compressed body and inhabiting shallow coastal waters. the opah. any of various other rounded, silvery fishes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: moonfish (Thesaurus) moon-faced moonflower Related Content Daily Word Quiz: rotund Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language