Nationalization is the act, or the policy, of a government taking over a large industry — water, gas, the railways, oil, sometimes banks — so that the state owns it or runs it, instead of private companies. It is the noun that names what happens when a government nationalizes something. You will meet it in news, history, and political argument: “the nationalization of the coal mines.” Some people hear a promise of fairer, cheaper public services; others hear the state grabbing too much. The opposite idea is privatization: selling those things back to private owners. British spelling is often nationalisation. This word is about ownership and control of industries, not about a person’s passport or a crowd’s pride.