From a (as negative particle) and eido; properly, unseen, i.e. "Hades" or the place (state) of departed souls -- grave, hell.
see GREEK a
see GREEK eido
ᾅδῃ (adē) − 1 Occurrence
ᾅδην (adēn) − 2 Occurrences
ᾅδης (adēs) − 3 Occurrences
ᾅδου (adou) − 4 Occurrences