/ Dictionary / Index T topminnow: Meaning and Definition of Find definitions for: top•min•now Pronunciation: (top'min"ō), [key] — pl. -now, -nows. any of several small, surface-swimming fishes of the egg-laying family Cyprinodontidae and the live-bearing family Poeciliidae, some of which are used in mosquito control. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: topminnow (Thesaurus) topmaul topmost Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language