Nantucket vs island

Nantucket and island both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nantucket	Yes	No	No	No
island	Yes	No	No	No

Nantucket (noun)	island (noun)
an island resort off Cape Cod; formerly a center of the whaling industry	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water