/ Dictionary / Index R radiance: Meaning and Definition of Find definitions for: ra•di•ance Pronunciation: (rā'dē-uns), [key] — n. radiant brightness or light: the radiance of the tropical sun. warm, cheerful brightness: the radiance of her expression. radiation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: radiance (Thesaurus) radian radiancy Related Content Daily Word Quiz: modify Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language