/ Dictionary / Index U ultravirus: Meaning and Definition of Find definitions for: ul•tra•vi•rus Pronunciation: (ul"tru vī'rus), [key] — pl. -rus•es. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ultra vires ulu Related Content Daily Word Quiz: slough Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language