(Φλεγέθων), i. e. the flaming, a river in the lower world, is described as a son of Cocytus; butheis more commonly called Pyriphlegethon. (Verg. A. 6.265, 550; Stat. Tolwb. 4.522.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890