What is the social order in history?

The social structure in history denotes the form of government in a particular era. The device of specific eras is also distinguished. For example, in many countries there used to be a slave-owning social system, but over time it changed to a feudal one with a pronounced feudal ladder, almost all countries were characterized by this system. Then there was the capitalist system with a pronounced parliamentarianism. They also distinguish the communist system, which was in the USSR and a number of other states.