/ Dictionary / Index O OCS: Meaning and Definition of Find definitions for: OCS Pronunciation: [key] officer candidate school. Old Church Slavonic. outer continental shelf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ocreate oct- 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