Britain vs Oxbridge

Britain and Oxbridge both are nouns.

Word	Noun	Adjective	Verb	Adverb
Britain	Yes	No	No	No
Oxbridge	Yes	No	No	No

Britain (noun)	Oxbridge (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	general term for an ancient and prestigious and privileged university (especially Oxford University or Cambridge University)