Styx, in Grecian mythology, the dark river of the nether world in whose name the gods uttered their irrevocable vows. Styx is described as a daughter of Oceanus and Tethys, and as married to the Titan Pallas, by whom she became the mother of Zelus, Nice, Cratus, Bia and others. With her children she dwelt in a magnificent palace in Tartarus, which rested on silver columns and had its roof of stone raised up until it almost touched the heavens. By Zeus she became the mother of Persephone (Apollod. 1, 3, 1), and by Peiras of Echidna (Pausan. 8, 16, 1). Although a goddess, Styx appears to have been excluded from the society of the gods.