/ Dictionary / Index S spongefly: Meaning and Definition of Find definitions for: sponge•fly Pronunciation: (spunj'flī"), [key] — pl. -flies. any of several insects of the family Sisyridae, the aquatic larvae of which feed on freshwater sponges. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: spongefly (Thesaurus) sponged ware sponge iron Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language