ha·des \ˈhāˌdēz\noun (pluralhades) Usage: usually capitalized Etymology: from Hades, god of the underworld, abode of the dead in Greek mythology, from Greek Haidēs, Aidēs 1.: the abode or state of the dead : the place of departed spirits — compare netherworld, sheol 2.: hell < go to hades > < hotter than hades out on the firing range > < what in hades are you doing here >