Zetland vs Shetland

Zetland and Shetland both are nouns.

Word	Noun	Adjective	Verb	Adverb
Zetland	Yes	No	No	No
Shetland	Yes	No	No	No

As nouns, Zetland and Shetland are synonyms defined as:

Zetland and Shetland: an archipelago of about 100 islands in the North Atlantic off the north coast of Scotland

Other synonyms of Zetland include Shetland Islands.

Zetland (noun)	Shetland (noun)
an archipelago of about 100 islands in the North Atlantic off the north coast of Scotland	a small sheepdog resembling a collie that was developed in the Shetland Islands
	an archipelago of about 100 islands in the North Atlantic off the north coast of Scotland