While today many nations appear to co-incide with an independent state (a nation-state), this happenstance occured comparitively rarely in pre-modern history; the rise of nationalism in the 18th and 19th century saw the idea that each nation deserves its own state gain momentum in Europe. Today too, however, many nations exist without a state, such as the Kurds and the native American nations, whereas many states comprise several nations, such as Belgium and Spain.
In common usage, terms such as nation, country, land and state often appear as near-synonyms, i.e., for a territory under a single sovereign government, or the inhabitants of such a territory, or the government itself; in other words, a de jure or de facto state.
The idea of a nation remains somewhat vague, in that there is generally no strict definition for exactly who is considered to be a member of any particular nation. Many modern states show a great diversity of cultural behaviours and ethnic backgrounds. England may furnish a classic example: a territory which is not a state, since it has no government of its own, and which has large immigrant populations and diverse cultural behaviour, yet which is often described as a nation.
Governments of stable nation-states may address this problem by granting nationality, sometimes distinguished from citizenship, to those who have one or both parents already possessing nationality, or who are born within the country in question. When granting nationality to immigrants, authorities sometimes apply language and cultural knowledge tests, but now often ignore ethnicity in order to avoid racism and/or the accusation thereof.
Groups which are in some way culturally coherent (or who claim to be) are sometimes described as nations, despite not sharing a territory (see diaspora). Examples of such concepts include the Romany nation, the Jewish nation (especially before the creation of the state of Israel), the Melungeon nation and the Queer nation.