achromatism; colorlessness
Technical term in optics and physics for the absence of chromatic aberration or color. Also used as an adjectival noun meaning 'achromatic'.
An achromatic lens corrects chromatic aberration.
この望遠鏡は色消しの設計を採用している。
This telescope employs an achromatic design.
Compound of 色 (color) and 消し (erasing, from 消す). Literally 'color erasing', referring to the removal of color fringing in optics.