di·chro·ma·tism 
(dī-krōmə-tĭz′əm) also di·chro·mism (-mĭz′əm)
(dī-krōmə-tĭz′əm) also di·chro·mism (-mĭz′əm)n.
1. The quality or condition of having or exhibiting two colors.
2. A form of colorblindness in which only two of the three fundamental colors can be distinguished due to a lack of one of the cone pigments.
di′cro·matic (-mătĭk) adj.