Catalina Island vs island

Catalina Island and island both are nouns.

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

Catalina Island (noun)	island (noun)
an island resort in the Pacific off the southwestern coast of California	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water