COCYTUS, one of the rivers of hell, according to the theology of the poets. It derives its name αὐτὸν κωκύτη, from groaning and lamenting. Hence Milton,
Cocytus named, of lamentation loud,
Heard on the rueful stream.
Cocytus was a branch of the river Styx, and, according to Horace, flowed with a dull and languid stream.