Isle of Man vs island

Isle of Man and island both are nouns.

Word	Noun	Adjective	Verb	Adverb
Isle of Man	Yes	No	No	No
island	Yes	No	No	No

Isle of Man (noun)	island (noun)
one of the British Isles in the Irish Sea	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water