/ Dictionary / Index F flatfish: Meaning and Definition of Find definitions for: flat•fish Pronunciation: (flat'fish"), [key] — pl. -fish, -fish•es. any fish of the order Heterosomata (Pleuronectiformes), including the halibut, sole, flounder, etc., having a greatly compressed body and swimming on one side, with both eyes on the upper side in the adult. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: flatfish (Thesaurus) flat-file flatfoot Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language