/ Dictionary / Index O optical glass: Meaning and Definition of Find definitions for: op'tical glass' Pronunciation: [key] — Optics. Optics. any of several types of high-quality, homogeneous, color-free glass, as flint or crown glass, having specified refractive properties, used in lenses and other components of optical systems. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. optical fiber optical illusion Related Content Daily Word Quiz: acerbity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language