Great Britain vs Home Counties

Great Britain and Home Counties both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
Home Counties	Yes	No	No	No

Great Britain (noun)	Home Counties (noun)
an island comprising England and Scotland and Wales	the English counties surrounding London into which Greater London has expanded
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