British Isles vs Great Britain

British Isles and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
British Isles	Yes	No	No	No
Great Britain	Yes	No	No	No

British Isles (noun)	Great Britain (noun)
Great Britain and Ireland and adjacent islands in the north Atlantic	an island comprising England and Scotland and Wales
	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