/ Dictionary / Index R R.I.B.A.: Meaning and Definition of Find definitions for: R.I.B.A. Pronunciation: [key] Royal Institute of British Architects. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rib ribald Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language