/ Dictionary / Index R RBC: Meaning and Definition of Find definitions for: RBC Pronunciation: [key] red blood cell. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: rbc (Thesaurus) Rb R.B.I. 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