Despotism is rule by a despot: a system in which one person holds great power and uses it in a cruel and unfair way. It names the arrangement, not the man or woman on the throne. You meet it in history and political writing — a fight against despotism, years of despotism, the evils of despotism. It can also mean that style of control more generally, even when people are talking about a workplace, though that is a stretch from the political core. Though actually, history books also speak of enlightened despotism: rulers who kept almost all the power but claimed to use it for the people’s good. That phrase does not make the rule kind in our ordinary sense; it only marks a debate about whether total power was ever used well. In everyday English, dictatorship is the more common news word; despotism sounds a little older and more literary.