/ 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: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language