"An extensive aggregate of persons, so closely associated with each other by common descent, language, or history, as to form a distinct race or people, usually organized as a separate political state and occupying a definite territory."
This usage dates in English back to the 1300s, with a first example that I won't type because I'm not sure where the letter thorn is hiding; the second is "All naciun and lede aglit vr lauerd for to drede," from Crsor M, 1300. (Geeze, I need a magnifying glass or better cheaters.)
It enters English from French, and before from Latin (that is an 'L', right?): nation-em, "breed, stock, race, nation", from nasci, "to be born".
But it goes on to say, "In early examples the racial idea is usually stronger than the political; in recent use the notion of political unity and independence is more prominent." An example is from 1872, "In Switzerland four languages are spoken; yet the Swiss certainly make one nation."
From reading David Reynolds, my understanding is that the use of "nation" to mean a culturally-related (or "racially", or "historically", or something) group of people that ought to be a political unit, and vice versa, that a political unit ought to be a somehow-related group of people, is a relatively recent thing, possibly a gift of Woodrow Wilson following WWI. (Think of the phrase "nation-state".)
[Word of the day: "Natiform": Resembling or having the form of buttocks. Thanks, OED!]
https://www.bbc.co.uk/programmes/b07zz5mf
The philosopher and cultural theorist Kwame Anthony Appiah argues against a mythical, romantic view of nationhood, saying instead it should rest on a commitment to shared values.
He explores the history of the idea, born in the 19th century, that there are peoples who are bound together by an ancient common spirit and that each of these nations is entitled to its own state. He says this idea is a mistaken one, illustrating his argument through the life story of the writer who took the pen name Italo Svevo - meaning literally Italian Swabian. He was born a citizen of the Austro-Hungarian Empire and became a citizen of the new republic of Italy, all without leaving his home city of Trieste. Appiah argues that states exist as a set of shared beliefs rather than membership of some sort of mythical and ancient group. "What binds citizens together is a commitment," he says, "to sharing the life of a modern state, united by its institutions, procedures and precepts."
The lecture is recorded in front of an audience at the University of Glasgow. The series is presented and chaired by Sue Lawley. Future lectures will examine the themes of colour and culture.