Vancouver Island vs island

Vancouver Island and island both are nouns.

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

Vancouver Island (noun)	island (noun)
an island off southwestern Canada (off the southwestern coast of British Columbia); the largest island off the west coast of North America	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water