United Kingdom of Great Britain and Northern Ireland vs mac

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

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

United Kingdom of Great Britain and Northern Ireland (noun)	mac (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	a waterproof raincoat made of rubberized fabric