In Greek mythology, Cocytus, meaning river of wailing (Greek kokutos, "lamentation") was the river in the underworld on the banks of which the dead who could not pay Charon wandered, according to most accounts for one hundred years. It flowed into the river Acheron, across which lay Hades, the mythological abode of the dead.

In The Divine Comedy (Inferno), Cocytus is the ninth and lowest circle of Hell and is frozen by the flapping wings of Lucifer, or Satan. In the Inferno Cocytus is referred to as a frozen lake rather than a river, although it originates from the same source as the other infernal rivers. Dante described it as being the home of traitors and those who committed acts of complex fraud. It is divided into four descending "rounds," or sections:

• Caina , after the Biblical Cain; traitors to blood relatives.
• Antenora , after Antenor from the Iliad; traitors to country.
• Ptolomea , after Ptolemy, governor of Jericho, who murdered his guests (1 Maccabees); traitors to guests.
• Judecca , after Judas Iscariot; traitors to masters and benefactors.

Lucifer is at the center of the circle, and is depicted with three mouths. One mouth gnaws on Brutus and another on Cassius, the leading conspirators against Julius Caesar, and both are chewed feet foremost with their heads protruding. Judas is chewed head foremost in the centre mouth.