/ Dictionary / Index F fifteen: Meaning and Definition of Find definitions for: fif•teen Pronunciation: (fif'tēn'), [key] — n. a cardinal number, ten plus five. a symbol for this number, as 15 or XV. a set of this many persons or things. —adj. amounting to 15 in number. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fifteen (Thesaurus) FIFO fifteenth Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language