United Kingdom of Great Britain and Northern Ireland vs gun room

United Kingdom of Great Britain and Northern Ireland and gun room both are nouns.

Word	Noun	Adjective	Verb	Adverb
United Kingdom of Great Britain and Northern Ireland	Yes	No	No	No
gun room	Yes	No	No	No

United Kingdom of Great Britain and Northern Ireland (noun)	gun room (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	military quarters of midshipmen and junior officers on a British warship