/ Dictionary / Index I in vacuo*: Meaning and Definition of Find definitions for: in va•cu•o Pronunciation: (in wä'koo-ō" Eng. in vak'y&oomacr-ō"), [key] — Latin. Latin. in a vacuum. in isolation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. inv. invade Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language