United Kingdom of Great Britain and Northern Ireland vs estate of the realm

United Kingdom of Great Britain and Northern Ireland and estate of the realm both are nouns.

Word	Noun	Adjective	Verb	Adverb
United Kingdom of Great Britain and Northern Ireland	Yes	No	No	No
estate of the realm	Yes	No	No	No

United Kingdom of Great Britain and Northern Ireland (noun)	estate of the realm (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 major social class or order of persons regarded collectively as part of the body politic of the country (especially in the United Kingdom) and formerly possessing distinct political rights