/ Dictionary / Index R riverbed: Meaning and Definition of Find definitions for: riv•er•bed Pronunciation: (riv'ur-bed"), [key] — n. the channel in which a river flows or formerly flowed. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: riverbed (Thesaurus) river basin river birch Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language