Gulf of Mexico vs Tampa Bay

Gulf of Mexico and Tampa Bay both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gulf of Mexico	Yes	No	No	No
Tampa Bay	Yes	No	No	No

Gulf of Mexico (noun)	Tampa Bay (noun)
an arm of the Atlantic to the south of the United States and to the east of Mexico	an arm of the Gulf of Mexico in west central Florida