/ Dictionary / Index R Rainier III: Meaning and Definition of Find definitions for: Rai•nier III Pronunciation: (rā-nēr', re-, ru- Fr. re-nyā'), [key] born 1923, reigning prince of Monaco since 1949. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Rainier rainmaker Related Content Daily Word Quiz: penury Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language