A subcontinent is a large mass of land that is almost big enough to be a continent. Greenland is a subcontinent.
Greenland.
Possibly you are thinking of Greenland, which is a very large island, but not quite a continent.
Greenland
Godthab, now Nuuk, is the capital of Greenland. It is located in North America.
Greenland
Greenland.
Greenland.
Greenland
Greenland.
By geographic convention, a continent is a continent and NOT an island. Therefore, Greenland is the largest island in the world (as part of North America) and Australia is a continent.
Australia is considered by some to be an island and a continent. It is the world's smallest continent, and it is an island because it is entirely surrounded by water. However, it is theoretically too large to be considered an island. The world's largest island is Greenland.