/ Dictionary / Index U um: Meaning and Definition of Find definitions for: um Pronunciation: (um, un, um, un), [key] — interj. (used as an expression of doubt, hesitation, deliberation, interest, etc.) Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Ulysses Umayyad Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language