the Phlegethon, river of fire in the underworld
Latin word, found 18 times in the texts on Socratos.
Vergil, Aeneid 6.265: et Chaos, et Phlegethon, loca nocte tacentia late,
Seneca the Younger, Phaedra 848: Phlegethonte ab imo petere longinquum aethera
Seneca the Younger, Agamemnon 753: Phlegethontis atri regias animas vehet,