And some of the smaller countries, such as Belgium, which contains two distinct national identities: the Flemish and the French speaking. Geographically these two nationalities are quite polarised and form separate federated states within the sovereign state of Belgium. These are states that are members of a Federal Union; for whatever reason they view it as more beneficial to retain a certain degree of self-governance while also committing a significant portion of their ability to govern and decisions relevant to a central federal government. The collective of which is referred to as a sovereign state an entity which has it's own Government, maintains borders and is usually recognised by other sovereign states as being independent. The UN is a committee populated by member sovereign states. It was called the UN because the US was already in the common lexicon as referring to the United States of America but that doesn't make nation the "correct" term for use, hell look at the UN Charter where
membership is only open to states, not nations.
Not that I especially enjoy referring to wikipedia when I could be Harvard referencing; quoting blocks of textbooks (and I mean BLOCKS) and typing up lecture notes the relevant pages are pretty good at giving a brief but correct overview.
Nation State. The nation-state is a certain form of state that derives its political legitimacy from serving as a sovereign entity for a nation as a sovereign territorial unit.
Sovereign State. A sovereign state, commonly simply referred to as a state, is a political association with effective internal and external sovereignty over a geographic area and population which is not dependent on, or subject to any other power or state.
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In casual usage, the terms "country", "nation", and "state" are often used as if they were synonymous; but in a more strict usage they can be distinguished:
* Nation denotes a people who are believed to or deemed to share common customs, origins, and history. However, the adjectives national and international also refer to matters pertaining to what are strictly sovereign states, as in national capital, international law.
* State refers to the set of governing and supportive institutions that have sovereignty over a definite territory and population.
Federated State. A federated state, commonly simply referred to as a state, is a territorial and constitutional community forming part of a federal union.[1] Such states differ from sovereign states, in that they have transferred a portion of their sovereign powers to a federal government.[2] A federated state holds administrative jurisdiction over a defined geographic territory and is a form of regional government.
Nation. A nation is a body of people who share a real or imagined common history, culture, language or ethnic origin.
You will excuse me if I defer faith in the definition to the PhDs teaching me.