The meaning of 'color' (blue, red,

The meaning of 'color' (blue, red, white, yellow, green and so on) is common knowledge.
It is easy to imagine what a variable or a constant of color type may mean.
It is a constant or a variable,
the value of which is a color.
It may seem to be a bit unusual,
but it is very simple, generally speaking. Like the value of an integer constant is a number,
the value of a color constant is a color.