However, the idea of race is not just about the colour of one's skin but also about ethnicity which takes into account physical features, language, religion, ideas of nation and culture. These are the things people use to define themselves as a group. Often when people refer to different races they use now one criterion, now another. Academics are increasingly putting the word 'race' in quotation marks to show that it is an ill-defined and misleading term. More clear is how the notion of race is used.
Racism is about people from dominant groups exerting their power unjustly over others.
The only justification they can offer for their behaviour is that they belong to a 'superior' race. In the past racist science attempted to prove this. I had the misfortune to be taught this in Geography class at school. Despite the staying power of such pseudoscientific mumbo, the facts are very different. The genetic differences within such so-called 'races' are greater than those between them.