island vs Long Island

island and Long Island both are nouns.

Word	Noun	Adjective	Verb	Adverb
island	Yes	No	No	No
Long Island	Yes	No	No	No

island (noun)	Long Island (noun)
a zone or area resembling an island	an island in southeastern New York; Brooklyn and Queens are on its western end
a land mass (smaller than a continent) that is surrounded by water