Hue is the most obvious and refers to the wavelength of light visible. In other words whether it is red or green or blue.

2 - The word ‘hue’ is often found on cheaper tubes of paint. It indicates where the correct pigment has been replaced by another, or by a mixture to imitate the real thing. This is rarely a complete success, but it does save a lot of money for the manufacturer, and enables you to obtain a colour for a lot less money than it would do otherwise.