/ Dictionary / Index I irradiance: Meaning and Definition of Find definitions for: ir•ra•di•ance Pronunciation: (i-rā'dē-uns), [key] — n. Physics. incident flux of radiant energy per unit area. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Irra irradiant Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language