/ Dictionary / Index F firefly: Meaning and Definition of Find definitions for: fire•fly Pronunciation: (fīr'flī"), [key] — pl. -flies. any nocturnal beetle of the family Lampyridae, characterized by a soft body with a light-producing organ at the rear of the abdomen. Also calledCf. glowworm. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: firefly (Thesaurus) firefighter fire gilding 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