achromat achromat /əˈkroʊmæt/

noun

1. A compound lens system that forms an image free from chromatic aberration  ( achromatic lens , achromat )
   a compound lens system that forms an image free from chromatic aberration
    The scientist used the achromatic lens in his telescope to obtain images without chromatic aberration.
   The scientist used the achromatic lens in his telescope to obtain images without chromatic aberration.