monochromatism

noun

1. the quality of having one color: the monochromatism of Picasso’s Blue Period.
2. Ophthalmology. a defect of vision in which the retina fails to perceive color.Compare dichromatism(def 2), trichromatism(def 3).

noun

1. a visual defect in which all colours appear as variations of a single hue

n.

1. The state of having or exhibiting only one color.
2. achromatopsia