Dominica vs island

Dominica and island both are nouns.

Word	Noun	Adjective	Verb	Adverb
Dominica	Yes	No	No	No
island	Yes	No	No	No

Dominica (noun)	island (noun)
a country on the island of Dominica	a zone or area resembling an island
a volcanic island in the Windward Islands that was once a stronghold of the Carib Indians	a land mass (smaller than a continent) that is surrounded by water