(n-)dol (“hill”), (n-)gûl (“magic”) + dûr (“dark”)
noun. hill of dark magic
place name. Hill of Sorcery
Conceptual Development: In Lord of the Rings drafts from the 1940s, this name first appeared as (Ilk.?) Dol Dúghol (TI/178), with several variations in the second element as Tolkien worked through the drafts (sometimes u instead of o, sometimes gh instead of g). The form Dol Guldur did not appear until very late in Tolkien’s writing (WR/122).
Word Gloss dol(l) “head, hill” guldur “black arts, sorcery”