Abaddon, a Hebrew word signifying
(I) ruin, destruction (Job, xxxi, 12);
(2) place of destruction; the Abyss, realm of the dead (Job, xxvi, 6; Prov., xv, 11);
(3) it occurs personified (Apoc., ix, 11) as Abaddon, and is rendered in Greek by Apolluon, denoting the angel-prince of hell, the minister of death and author of havoc on earth. The Vulgate renders the Greek Apollyon by the Latin Exterminans (that is, "Destroyer"). The identity of Abaddon with Asmodeus, the demon of impurity, has been asserted, but not proved.
In Job, xxvi, 6, and Prov., xv, 11, the word occurs in conjunction with Sheol.