island vs dry land

island and dry land both are nouns.

Word	Noun	Adjective	Verb	Adverb
island	Yes	No	No	No
dry land	Yes	No	No	No

As nouns, dry land is a hypernym of island; that is, dry land is a word with a broader meaning than island:

Other hypernyms of island include earth, ground, land, solid ground, terra firma.

island (noun)	dry land (noun)
a zone or area resembling an island	the solid part of the earth's surface
a land mass (smaller than a continent) that is surrounded by water