Gulf Coast of the United States vs geographic area

Gulf Coast of the United States and geographic area both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gulf Coast of the United States	Yes	No	No	No
geographic area	Yes	No	No	No

Gulf Coast of the United States (noun)	geographic area (noun)
a region of the United States comprising states bordering the Gulf of Mexico; Alabama and Florida and Louisiana and Mississippi and Texas	a demarcated area of the Earth