Achromatism

noun

1. The state or quality of being achromatic; absence of coloration: as, to secure perfect achromatism in a telescope.
2. The state or quality of being achromatic; ; achromaticity.

   "the achromatism of a lens"

3. The state or quality of being achromatic; as, the achromatism of a lens; achromaticity.
4. The state of being free of colors, not emitting or separating into colors.
5. Achromatopia.