The ash Yggdrasil suffers anguish More that men can know: The stag bites above; on the side it rots; And the dragon gnaws from beneath … its name, Yggdrasil, means ‘The horse of Ygg,’ whose other name is Odin; for this great god once hung on that tree nine days
Campbell presents the full mythic complex of Yggdrasil — cosmic structure, sacrificial ordeal, and etymology — as the paradigmatic Germanic instance of the World Tree, situating it within a comparative sequence of universal images.
, Primitive Mythology (The Masks of God, Volume I), 1959thesis