Meaning of optical glass

op'tical glass'

Pronunciation: [key]
— Optics. Optics.
  1. 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.