Ilk. Dol Dúghol loc.
An earlier name for Dol Guldur appearing in Lord of the Rings drafts from the 1940s (WR/122), with variations Dol Dúgol (TI/178) and Dol Dûghul (TI/244). The word dûghol appears an earlier rejected word for “sorcery” in The Etymologies (EtyAC/ÑGOL), so perhaps this word was originally intended to be Ilkorin.
See S. Dol Guldur for further discussion.
References ✧ PMI/Dol Guldur; TI/178, 244, 296; TII/Dol Dúgol; WR/122; WRI/Dol Dúghol