Nation state

A nation state, or nation-state, is a political entity in which the state (a centralized political organization ruling over a population within a territory) and the nation (a community based on a common identity) are congruent.

A nation, sometimes used in the sense of a common ethnicity, may include a diaspora or refugees who live outside the nation-state; some dispersed nations (such as the Roma nation, for example) do not have a state where that ethnicity predominates. In a more general sense, a nation-state is simply a large, politically sovereign country or administrative territory.

Historians and scholars of nationalism studies are divided over whether nations preceded nation-states or if nation-states produced nationalism, but are agreed that the nineteenth century, after the age of revolutions, was a key period for the rise of nation states.