/ Dictionary / Index I in vivo: Meaning and Definition of Find definitions for: in vi•vo Pronunciation: (in vē'vō), [key] (of a biological process) occurring or made to occur within a living organism or natural setting. Cf. in vitro. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. in vitro fertilization invocate Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language