/ Dictionary / Index O OSS: Meaning and Definition of Find definitions for: OSS Pronunciation: [key] Office of Strategic Services: a U.S. government intelligence agency during World War II. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. OSRD ossa Related Content Daily Word Quiz: abstain Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language