geographic region vs Caucasia

geographic region and Caucasia both are nouns.

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

geographic 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