Colours are split up into three main groups. These groups are called :
The primary colours are Red, Blue and Yellow. These are the base colours from which all the other colours in the colour wheel come from and cannot be made by mixing any of the colours from the colour wheel together.
The secondary colours such as Green, Orange and Violet are obtained by mixing the 2 primary colours together. For example Red and Yellow would be mixed together to create Orange.
The tertiary colours are obtained by mixing a primary colour with a secondary colour. For example if you mix the primary Red with the secondary Orange you will achieve a darker Orange.