1911 Encyclopædia Britannica/Cocytus

COCYTUS (mod. Vuvo), a tributary of the Acheron, a river of Thesprotia (mod. pashalik of Iannina), which flows into the Ionian Sea about 20 m. N. of the Gulf of Arta. The name is also applied in Greek mythology to a tributary of the Acheron or of the Styx, a river in Hades. The etymology suggested is from κωκύειν, to wail, in allusion to the cries of the dead. Virgil describes it as the river which surrounds the underworld (Aen. vi. 132).