According to legend, Disko Island was pulled north from the south, by two strong kayakers, using a single strain of hair from a newborn baby. The kayakers were going strong until they reached the what is known today as Disko Bay, where a Witch from Ilulissat spotted them and put a curse on them, stopping them from going further north.
Which isn't too far from reality, Disko Island did indeed come from somewhere else! It's a volcanic island, much younger than the rest of Greenland, which rose up from the continental split where you now find Iceland. The volcanic soil is rich in nutrients and therefore far greener than the mainland on the same longitude. It also means that the rocks and mountains differ greatly from anywhere else in Greenland.
In Greenlandic, the island is named Qeqertarsuaq - “The big island”, which means that the word Disko has come from somewhere else. Some say that it is because the island is so rounded that the name comes from the Greek word Diskos - as in the disc you throw. Others are sure that it’s slang for Discovery Island, there is even an article from 1883 claiming that it is because the mountains with the flat tops look like the Danish desks.
The name seems to have its first appearance on a Dutch map over Spitzbergen, first as Dusko, then later as Dicko. The precursor for this seems to have been from Ducke’s coue or Duck’s bay, named after an English explorer and whaler - Marmaduke. It is believed that the name has simply been copied from Spitzbergen to Greenland when whaling became more popular in those waters.
In any case, the Disko Island and the Disko Bay have stunning natural landscapes, and I wholeheartedly recommend travelling there, even though we’re not quite sure how it got its name.