Breadcrumb Home > Dictionary > Index I IRB: Meaning and Definition of Find definitions for: IRB Pronunciation: [key] industrial revenue bond. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Irazu Irbid ✖ Related Content Daily Word Quiz: hortatory Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language