Admiralty Island vs island

Admiralty Island and island both are nouns.

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

Admiralty Island (noun)	island (noun)
an Alaskan island in the Alexander Archipelago near Juneau	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water