apochromatic objective

[ ăp′ə-krō-mătĭk ]

n.

An objective in which chromatic aberration is corrected for three colors and spherical aberration is corrected for two.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.