Whence dwimmerlaik?

[The Squatter of Amon Rûdh]

As luck would have it, I was skimming through Letters earlier (looking for something else that wasn't there), and found this.

I am afraid I have been far too casual about 'magic', and especially the use of the word... I do not intend to involve myself in any debate whether 'magic' in any sense is real or really possible in the world. But I suppose that, for the purposes of the tale, some would say that there is a latent distinction between magia and goeteia. Galadriel speaks of the 'deceits of the Enemy'. Well enough, but magia could be, was held good (per se), and goeteia bad. Neither is, in this tale, good or bad (per se), but only by motive or purpose or use. Both sides use both, but with different motives. The supremely bad motive is (for this tale, since it is specifically about it) domination of other 'free' wills.

Letters #155 (draft)

A footnote goes on to explain that goeteia is Greek for 'sorcery' and that English goety (a loan from Greek) is witchcraft by incantation, the use of spirits or necromancy (emphasis mine).