United Kingdom of Great Britain and Northern Ireland vs Home Counties

United Kingdom of Great Britain and Northern Ireland and Home Counties both are nouns.

Word	Noun	Adjective	Verb	Adverb
United Kingdom of Great Britain and Northern Ireland	Yes	No	No	No
Home Counties	Yes	No	No	No

United Kingdom of Great Britain and Northern Ireland (noun)	Home Counties (noun)
a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland; `Great Britain' is often used loosely to refer to the United Kingdom	the English counties surrounding London into which Greater London has expanded