Of or pertaining to hell.
Of, pertaining to or resembling Acheron (one of the rivers located in the underworld according to ancient Greek mythology).
Lacking joy and comfort; nearing death.
Pertaining to Hades or hell.
Of, or relating to the geological eon.
The Hadean eon; part of the Precambrian supereon, spanning from around 4.6 to 4 billion years ago.