/ Dictionary / Index U ultraism: Meaning and Definition of Find definitions for: ul•tra•ism Pronunciation: (ul'tru-iz"um), [key] — n. extremism. an extremist point of view or act. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ultrahigh frequency ultralarge crude carrier Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language