noun
: a compound lens made by combining lenses of different material (as flint glass and crown glass) having different focal powers, the light that emerges from the lens forming images practically free from prismatic colors
noun
: a compound lens made by combining lenses of different material (as flint glass and crown glass) having different focal powers, the light that emerges from the lens forming images practically free from prismatic colors
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012