Hue
Where a colour sits on the colour wheel: red, yellow, green, blue, violet, and round again.
See it in FX engine. Under Adjustments, move Hue and watch every colour turn round the wheel.
In plain words
Hue is the part of a colour we name: red, orange, green or blue. It is measured as an angle on a wheel, from 0 to 360 degrees. Red sits at 0, green at 120 and blue at 240. Turning the hue moves a colour round the wheel while its strength and lightness stay the same. Grey, white and black have no hue at all.