/ Dictionary / Index R RRT: Meaning and Definition of Find definitions for: RRT Pronunciation: [key] See R.R.T. Pronunciation: [key] registered respiratory therapist. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. R.R.R. Rs. Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language