information:classification, structural:summarization
Etymology and terminology

The English word nation from Middle English c. 1300, nacioun "a race of people, large group of people with common ancestry and language," from Old French nacion "birth (naissance), rank; descendants, relatives; country, homeland" (12c.) and directly from Latin nationem (nominative natio (nātĭō), supine of verb nascar « to birth » (supine : natum)) "birth, origin; breed, stock, kind, species; race of people, tribe," literally "that which has been born," from natus, past participle of nasci "be born" (Old Latin gnasci), from PIE root *gene- "give birth, beget," with derivatives referring to procreation and familial and tribal groups.

In Latin, natio represents the children of the same birth and also a human group of same origin. By Cicero, natio is used for "people".

Black's Law Dictionary defines a nation as follows:

nation, n. (14c) 1. A large group of people having a common origin, language, tradition, and usage constitutes a political entity. When a nation is coincident with a state, the term nation-state is often used....

...

2. A community of people inhabiting a defined territory and organized under an independent government; a sovereign political state....

The word "nation" is sometimes used as synonym for:

Thus the phrase "nations of the world" could be referring to the top-level governments (as in the name for the United Nations), various large geographical territories, or various large ethnic groups of the planet.

Depending on the meaning of "nation" used, the term " nation state " could be used to distinguish larger states from small city states, or could be used to distinguish multinational states from those with a single ethnic group.