COCY′TUS (Lat., from Gk. Κωκυτός, Kokytōs, river of wailing, from κωκύειν, kōkyein, to wail. Skt. kū. to cry). A tributary of the Acheron in Epirus, now called Βωβός, Bōbos. Cocytus was also the name of a river of the infernal regions, a branch of the Styx.