/ Dictionary / Index I illuminometer: Meaning and Definition of Find definitions for: il•lu•mi•nom•e•ter Pronunciation: (i-l"mu-nom'i-tur), [key] — n. an instrument for measuring illumination. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. illuminism illus. 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