Styx was the main river of Hades, and its goddess. Like most river deities, she was a child of Oceanus and Tethys, and she married Pallas, the Titan, to whom she bore Zelus, Nike, Cratos and Bia.

The waters of the Styx were fatal to life, so that 'crossing the Styx' meant death and was to be feared and abhorred. Her name, thus, means, 'hated', 'abhorrent' (styx, stygos). (The word is not actually related to English 'stigma', as stated by some sources.)