Idrassil

Idrassil is the name of a concept art in The Art of World of Warcraft. It depicts a World Tree growing out of an island. There are currently only three known world trees on Azeroth, and they are Nordrassil, Vordrassil and Teldrassil respectively. Given only one of them grows out of an island, it is likely that Idrassil is an earlier concept name for the current Teldrassil.