UK vs rag day

UK and rag day both are nouns.

Word	Noun	Adjective	Verb	Adverb
UK	Yes	No	No	No
rag day	Yes	No	No	No

UK (noun)	rag day (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 day on which university students hold a rag