/ Dictionary / Index O operating room: Meaning and Definition of Find definitions for: op'erating room" Pronunciation: [key] a specially equipped room, usually in a hospital, where surgical procedures are performed. Abbr.: OR Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. operating income operating system Related Content Daily Word Quiz: heifer Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language