Tartarus (n.)youdaoicibaDictYouDict[Tartarus 词源字典]
in Homer and older Greek mythology, the sunless abyss below Hades, from Greek Tartaros, of uncertain origin; "prob. a word of imitative origin, suggestive of something frightful" [Klein]. Later in Greek almost synonymous with Hades.[Tartarus etymology, Tartarus origin, 英语词源]