Yggdrasil

noun Scandinavian Mythology.

1. an evergreen ash tree, the three roots of which bind together Asgard, Midgard, and Niflheim.

noun

1. Norse myth the ash tree that was thought to overshadow the whole world, binding together earth, heaven, and hell with its roots and branches

great tree of the universe, 1770, from Old Norse ygdrasill, apparently from Yggr, a name of Odin + drasill “horse.”