/ Dictionary / Index U ultimatum: Meaning and Definition of Find definitions for: ul•ti•ma•tum Pronunciation: (ul"tu-mā'tum, -mä'-), [key] — pl. -tums, -ta a final, uncompromising demand or set of terms issued by a party to a dispute, the rejection of which may lead to a severance of relations or to the use of force. a final proposal or statement of conditions. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ultimatum (Thesaurus) ultima Thule ultimo 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