/ Dictionary / Index I irisation: Meaning and Definition of Find definitions for: i•ris•a•tion Pronunciation: (ī"ri-sā'shun), [key] — n. the effect or quality of being iridescent; iridescence. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. iris iris diaphragm Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language