Erebus

in Homer, etc., the place of darkness between Earth and Hades, from Latin Erebus, from Greek Erebos, which is of unknown origin, perhaps from Semitic (compare Hebrew erebh "sunset, evening"), or from PIE *regw-es- "darkness" (source also of Sanskrit rajas "the atmosphere, thick air, mist, darkness;" Gothic rikwis "darkness"). Used figuratively of darkness from 1590s.