NATO vs Great Britain

NATO and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
NATO	Yes	No	No	No
Great Britain	Yes	No	No	No

NATO (noun)	Great Britain (noun)
an international organization created in 1949 by the North Atlantic Treaty for purposes of collective security	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