UK vs NATO

UK and NATO both are nouns.

Word	Noun	Adjective	Verb	Adverb
UK	Yes	No	No	No
NATO	Yes	No	No	No

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