Gulf of St. Lawrence vs gulf

Gulf of St. Lawrence and gulf both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gulf of St. Lawrence	Yes	No	No	No
gulf	Yes	No	No	No

Gulf of St. Lawrence (noun)	gulf (noun)
an arm of the northwest Atlantic Ocean off the southeastern coast of Canada	an unbridgeable disparity (as from a failure of understanding)
	a deep wide chasm
	an arm of a sea or ocean partly enclosed by land; larger than a bay