/ Dictionary / Index F filly: Meaning and Definition of Find definitions for: fil•ly Pronunciation: (fil'ē), [key] — pl. -lies. a young female horse. a girl or young woman. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: filly (Thesaurus) fill-up film Related Content Daily Word Quiz: ingenuity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language