Breadcrumb Home > Dictionary > Index A ATB: Meaning and Definition of Find definitions for: ATB Pronunciation: [key] all-terrain bike. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ataxia Atbara ✖ Related Content Daily Word Quiz: donnybrook Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language