European Union vs United Kingdom

European Union and United Kingdom both are nouns.

Word	Noun	Adjective	Verb	Adverb
European Union	Yes	No	No	No
United Kingdom	Yes	No	No	No

European Union (noun)	United Kingdom (noun)
an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members	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