/ Dictionary / Index U unless: Meaning and Definition of Find definitions for: un•less Pronunciation: (un-les', un-), [key] — conj. except under the circumstances that: I'll be there at nine, unless the train is late. —prep. except; but; save: Nothing will come of it, unless disaster. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. unleavened unlessoned Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language