Formosa vs island

Formosa and island both are nouns.

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

Formosa (noun)	island (noun)
an island in southeastern Asia 100 miles off the coast of mainland China in the South China Sea	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water