/ Dictionary / Index R river horse: Meaning and Definition of Find definitions for: riv'er horse" Pronunciation: [key] a hippopotamus. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. riverhead riverine Related Content Daily Word Quiz: lyre Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language