color coordinate system; colour system
Technical term in computing and color science for a system that defines colors using coordinates, such as RGB or CIELAB.
In image processing, conversion between color coordinate systems is often performed.
色空間 (color space) is a broader concept that includes the entire range of colors, while 色座標系 specifically refers to the coordinate system used to represent colors within that space.
Compound of 色 (color), 座標 (coordinates), and 系 (system). A straightforward technical term with no historical uncertainty.