region vs Western world

region and Western world both are nouns.

Word	Noun	Adjective	Verb	Adverb
region	Yes	No	No	No
Western world	Yes	No	No	No

region (noun)	Western world (noun)
a part of an animal that has a special function or is supplied by a given artery or nerve	the countries of (originally) Europe and (now including) North America and South America
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')