Abaddon is a Hebrew word signifying:

• ruin, destruction (Job 31:12);
• the place of destruction; the Abyss, realm of the dead (Job 26:6; Proverbs 15:11);
• it occurs personified (Apocalypse 9:11) as Abaddon and is rendered in Greek by Apollyon, 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 26:6, and Proverbs 15:11, the word occurs in conjunction with Sheol.