The Sindaril word for black magic, a compound of morn “black, dark” and gûl “(evil) knowledge” (PE17/125). Since the adjectival element “black” appears first in the word, this is probably an older compound, though its elements are still discernible. The word guldur is later compound of similar meaning, but with the adjectival element second.
Conceptual Development: The word N. morgul “sorcery” appeared in The Etymologies from the 1930s as a marginal note for the root ᴹ√ÑGOL (EtyAC/ÑGOL). In Lord of the Rings drafts from the 1940s, this word first appeared as N. morgol in the name N. Minas Morgol (TI/127), then later as N. morghul in the names N. Minas Morghul (TI/146) and N. Imlad Morghul (WR/223), before eventually being replaced by N/S. morgul everywhere. It therefore seems likely that the marginal note in The Etymologies was written after the introduction of this word in Lord of the Rings drafts.