/ Dictionary / Index O OTB: Meaning and Definition of Find definitions for: OTB Pronunciation: [key] offtrack betting. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Otaru OTC Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language