/ Dictionary / Index I identity matrix: Meaning and Definition of Find definitions for: iden'tity ma"trix Pronunciation: [key] — Math. Math. a matrix that has 1 in each position on the main diagonal and 0 in all other positions. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. identity element ideo- 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