geographical region vs Caucasia

geographical region and Caucasia both are nouns.

Word	Noun	Adjective	Verb	Adverb
geographical region	Yes	No	No	No
Caucasia	Yes	No	No	No

geographical region (noun)	Caucasia (noun)
a demarcated area of the Earth	a large region between the Black and Caspian seas that contains the Caucasus Mountains; oil is its major resource