region vs West

region and West both are nouns.

Word	Noun	Adjective	Verb	Adverb
region	Yes	No	No	No
West	Yes	No	No	No

region (noun)	West (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 region of the United States lying to the west of the Mississippi River
the extended spatial location of something	English painter (born in America) who became the second president of the Royal Academy (1738-1820)
a large indefinite location on the surface of the Earth	United States film actress (1892-1980)
the approximate amount of something (usually used prepositionally as in `in the region of')	British writer (born in Ireland) (1892-1983)