Monochromatism refers to the condition of seeing in only one color or shades of one color. Synonyms for this word include achromatopsy, which refers to a complete inability to see color, and monochromatopsia, which refers to seeing only shades of one color. Another synonym is dichromatism, which refers to the condition of seeing only two primary colors. This can occur in individuals who are colorblind and cannot distinguish between red and green, for example. Achromatic vision and monochromatic vision are also synonyms for monochromatism, denoting the inability to distinguish colors in the visible spectrum. Overall, these synonyms describe conditions in which the ability to perceive color is absent or limited.