Sign in to play this archived case and track your deductions.
A
Extremely dark, gloomy, or forbidding — evocative of the underworld, used to describe deep impenetrable darkness or a deeply oppressive atmosphere.
— OED
B
From the River Styx of Greek mythology, across which the souls of the dead were ferried by Charon to enter the underworld.
— Classical mythology
C
In biology, Stygian is used as a species epithet for cave-dwelling or deep-sea creatures that live in total darkness.
— Biological taxonomy
D
In classical antiquity, an oath sworn by the River Styx was considered the most binding oath possible — even the gods feared to break it.
— Hesiod, Theogony
E
The adjective was first used in English by John Milton in Paradise Lost to describe Satan's wings, and the Oxford English Dictionary cites this as the word's earliest recorded usage.
— OED first citation