/ Dictionary / Index N ninety-one: Meaning and Definition of Find definitions for: nine•ty-one Pronunciation: (nīn'tē-wun'), [key] — n. a cardinal number, 90 plus 1. a symbol for this number, as 91 or XCI. a set of this many persons or things. —adj. amounting to 91 in number. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ninety-one (Thesaurus) ninety-ninth ninety-second Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language