In sociology, Social class refers to the hierarchical distinctions between individuals or groups in societies or cultures.
There are various ways to divide classes. The working class do hard work for others. Where money is used, they are paid for it, but they seldom have much money. Where money is used little, as in feudalism, or not at all, as in the Inca Empire there are still classes.
Historians usually see two other groups - people who are rich or have a lot of influence, called the upper class, and all the remaining people who are in between, called the middle class.
Not all societies have social classes. Scientists have found no proof for hierarchical power structures during the Stone Age.[1]