Get a flashlight for this one

Boy, where did the last week go? I'd like to file a missing time report, please. Anyway, I am reading The Keep, a horror novel by F. Paul Wilson. I've just gotten to a part where one of the characters has entered the keep, which is occupied by a supernatural horror, through a secret entrance at its base:

Magda stood in the stygian gloom, shaking and indecisive.

Stygian sounded deliciously sinister, and its definitions bear that out. From the OED:

  • 1a. Pertaining to the river Styx, or, in wider sense, to the infernal regions of classical mythology.
  • 1b. Of an oath: Supremely binding, inviolable like the oath by the Styx, which the gods themselves feared to break.
  • 2. Infernal, hellish.
  • 3. Black as the river Styx; dark or gloomy as the region of the Styx.

Infernal. Another great word.

The Styx is prominent in Greek mythology. Again, from the OED: "A river of the lower world or Hades, over which the shades of the departed were ferried by Charon, and by which the gods swore their most solemn oaths."

The word Styx is Latin, from the Greek Stux, according to the American Heritage Dictionary. The Online Etymology Dictionary adds that it is related to the Greek stygos, meaning hatred, and stygnos, meaning gloomy