Anglesey Island vs island

Anglesey Island and island both are nouns.

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

Anglesey Island (noun)	island (noun)
an island to the northwest of Wales	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water