island vs Okinawa Island

island and Okinawa Island both are nouns.

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

island (noun)	Okinawa Island (noun)
a zone or area resembling an island	the largest island of the central Ryukyu Islands
a land mass (smaller than a continent) that is surrounded by water