/ Dictionary / Index O OIC: Meaning and Definition of Find definitions for: OIC Pronunciation: [key] officer in charge. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. OI OIcel Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language