Meaning of achromatic lens

ach'romat'ic lens'

Pronunciation: [key]
— Optics. Optics.
  1. a system of two or more lenses that is substantially free from chromatic aberration and in which the lenses are made of different substances so that the focal length of the system is the same for two or three wavelengths of light. Also calledCf. crown lens, flint glass.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.