Optics, Zoologythe quality or state of being dichromatic.
Also called di•chro•ma•top•si•a(dī krō′mə top′sē ə).USA pronunciation[Ophthalm.]a defect of vision in which the retina responds to only two of the three primary colors. Cf. monochromatism (def. 2), trichromatism (def. 3).