Sub-nationalism

There is no clear and precise definition of a nation. Examples:
 * 1) Is Great Britain 1 country?
 * 2) Is Great Britain 3 countries, England, Scotland and Wales?
 * 3) Should we be talking about Great Britain or about the United Kingdom of England, Scotland, and Walesand Nlorthern Ireland?
 * 4) Is the United Kingdom just part of a bigger nation, the European Union?

Presumably Sub-nationalism is identification with a group smaller than a nation however a nation is defined.