Brightness, hue, and saturation

These are the three attributes of color.

Brightness is the achromatic component, i.e., light power or intensity that detected by our eye.

Hue and saturation are the chromatic components. Simply defining,
Hue = wavelength;
Saturation = spectral purity.

Hue:
The wavelength that appears most prevalent in a color sample determines its hue. The set of basic hues, for example, 赤橙黄绿青蓝紫, is very subjective and differ from culture to culture.

Saturation:
"Spectral purity" is enough to define saturation. Lasers produce the most saturated colors whereas white-gray-black are the least saturated colors.

References:
1. Bruce Fraser, Chris Murphy, and Fred Bunting, Real World Color Management, 2nd ed. Peachpit Press 2005