A nation state is a type of state that joins the political entity of a state to the cultural entity of a nation, from which it aims to derive its political legitimacy to rule and potentially its status as a sovereign state. A state is specifically a political and geopolitical entity, whilst a nation is a cultural and ethnic one. The term "nation state" implies that the two coincide, in that a state has chosen to adopt and endorse a specific cultural group as associated with it.
The concept of a nation state can be compared and contrasted with that of the multinational state, city state,empire, confederation, and other state formations with which it may overlap. The key distinction is the identification of a people with a polity in the "nation state."
The origins and early history of nation states are disputed. A major theoretical question is: "Which came first, the nation or the nation state?" Scholars such as Steven Weber, David Woodward, and Jeremy Black have advanced the hypothesis that the nation state didn't arise out of political ingenuity or an unknown undetermined source, nor was it an accident of history or political invention; but is an inadvertent byproduct of 15th-century intellectual discoveries in political economy, capitalism, mercantilism, political geography, and geography combined together with cartography and advances in map-making technologies. It was with these intellectual discoveries and technological advances that the nation state arose. For others, the nation existed first, then nationalist movements arose for sovereignty, and the nation state was created to meet that demand. Some "modernization theories" of nationalism see it as a product of government policies to unify and modernize an already existing state. Most theories see the nation state as a 19th-century European phenomenon, facilitated by developments such as state-mandated education, mass literacy and mass media. However, historians also note the early emergence of a relatively unified state and identity in Portugal and the Dutch Republic.