/ Dictionary / Index E ellipsometer: Meaning and Definition of Find definitions for: el•lip•som•e•ter Pronunciation: (i-lip-som'i-tur, el"ip-, ē"lip-), [key] — n. Optics. an instrument that measures the ellipticity of polarized light, used for determining the thickness of thin films. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ellipsoidal ellipt Related Content Daily Word Quiz: cetacean Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language