- dichromacy, dichromatism, dichromatopsia, dichromia, dichromasy - a deficiency of color vision in which the person can match any given hue by mixing only two other wavelengths of light (as opposed to the three wavelengths needed by people with normal color vision)
--1 is a kind of color blindness, colour blindness, color vision deficiency, colour vision deficiency
--1 has particulars:red-green dichromacy, red-green color blindness, red-green colour blindness; yellow-blue dichromacy, yellow-blue color blindness