/ Dictionary / Index M March fly: Meaning and Definition of Find definitions for: March' fly" Pronunciation: [key] any of several flies of the family Bibionidae that appear during spring and early summer. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Marcheshvan march fracture Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language