Open University vs Great Britain

Open University and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
Open University	Yes	No	No	No
Great Britain	Yes	No	No	No

Open University (noun)	Great Britain (noun)
a British university that is open to people without formal academic qualifications and where teaching is by correspondence or broadcasting or summer school	an island comprising England and Scotland and Wales
	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