West Coast of the United States vs geographical region

West Coast of the United States and geographical region both are nouns.

Word	Noun	Adjective	Verb	Adverb
West Coast of the United States	Yes	No	No	No
geographical region	Yes	No	No	No

West Coast of the United States (noun)	geographical region (noun)
the western seaboard of the United States from Washington to southern California	a demarcated area of the Earth