The term 'A Primary Subtractive Color for Light' can be broken down into two crossword solutions: CYAN (4 letters) and MAGENTA (7 letters). CYAN and MAGENTA are both subtractive colors, meaning that when combined with other colors, they absorb some of the light, making the resulting color darker. They are also primary colors, meaning that they cannot be created by mixing other colors together. CYAN and MAGENTA are used in printing to create a wide range of colors, and are often used together to create shades of purple.