Colour
Red, yellow and blue are the primary colours. They are the main colours of the colour wheel. Every other colour is made out of the primary colours. You add white to tint the colour and add black to make it darker. You add primary colours to make the secondary colours. By adding red and blue you make violet, by mixing yellow and red you make orange, by mixing yellow and blue you make green.
Secondary colours are colours made by mixing two primary colours. They are orange, violet (or purple) and green. When you mix primary and secondary colours they make Tertiary colours.
Tertiary colours are colours that are mixed by the secondary and primary. There are 6 tertiary colours they are red-orange, yellow-orange, yellow-green, blue-green, blue-violet, and red-violet. The colours get their name by mixing the colours its named. For example blue-violet is named that because when you mix blue and violet that is the colour it makes.
This is the colour wheel. The triangle in the middle those are the primary colours. The colours outside are the secondary colours and the whole entire circle is the colour wheel. So each colour is made up of a primary colour red, yellow and blue.