/ Dictionary / Index R ria: Meaning and Definition of Find definitions for: ri•a Pronunciation: (rē'u), [key] — n. a long, narrow inlet of a river that gradually decreases in depth from mouth to head. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. RI rial Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language