island vs Sjaelland

island and Sjaelland both are nouns.

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

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