/ Dictionary / Index O O.S.B.: Meaning and Definition of Find definitions for: O.S.B. Pronunciation: [key] Order of St. Benedict (Benedictine). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Osasco Osbert Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language