Seeland vs island

Seeland and island both are nouns.

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

Seeland (noun)	island (noun)
the largest island of Denmark and the site of Copenhagen	a zone or area resembling an island
	a land mass (smaller than a continent) that is surrounded by water