Principality of Achaea vs region

Principality of Achaea and region both are nouns.

Word	Noun	Adjective	Verb	Adverb
Principality of Achaea	Yes	No	No	No
region	Yes	No	No	No

Principality of Achaea (noun)	region (noun)
a region of ancient Greece on the north coast of the Peloponnese	a part of an animal that has a special function or is supplied by a given artery or nerve
	a knowledge domain that you are interested in or are communicating about
	the extended spatial location of something
	a large indefinite location on the surface of the Earth
	the approximate amount of something (usually used prepositionally as in `in the region of')