/ Dictionary / Index R R.P.O.: Meaning and Definition of Find definitions for: R.P.O. Pronunciation: [key] Railway Post Office. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rpm RPQ Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language