A color space is a set of colors ...???? represented either as a 2D graph, or in 3D.
Exemples :
The colors that can be displayed by each medium (every screen, paper, projection screen, etc) can be represented on the color space.
By superimposing different color spaces, comparison is made easier.
Is the area of the triangle a good representation of the amount of the amount of colors that can be seen by humans ?