/ Dictionary / Index L lentivirus: Meaning and Definition of Find definitions for: len•ti•vi•rus Pronunciation: (len'tu-vī"rus), [key] — pl. -rus•es. any slow virus of the genus Lentivirus, of the retrovirus family, causing brain disease in sheep and other animals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. lentissimo lento Related Content Daily Word Quiz: sinister Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language