The standard definition of a ‘nation’ focuses on the idea of a population, usually in a distinct territory, that shares a common language, ethnic identity, history, religion and culture. ‘Nationalism’ is the political expression of this sense of national identity, most prominently in the claim to self-determination.
A state is a territorial political unit: a nation is a people sharing a particular identity, regardless of the political arrangements. Confusingly, many people use the words ‘nation’ and ‘state’ interchangeably. This is not the only confusion. True nation-states, in which a very high proportion of the citizenry share the same national identity, are rare. Out of today’s 196 sovereign state, there are only about ten proper nation-state, with Japan as the biggest. Most are multinational. The nation-state is therefore largely a fiction, though it has gained currency in international law. International relations, like all politics, are full of fuzzy language.