/ Dictionary / Index I improper fraction: Meaning and Definition of Find definitions for: improp'er frac'tion Pronunciation: [key] — Math. Math. a fraction having the numerator greater than the denominator. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. improper Improperia Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language