/ Dictionary / Index R Rhesus factor: Meaning and Definition of Find definitions for: Rhe'sus fac"tor Pronunciation: (rē'sus). [key] See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rhesus rhet. 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