Abaddon

Uh-bad´uhn; Heb., “destruction”

1. In the OT, the dwelling place of the dead. It is used as a synonym for Sheol, the Hebrew term for the underworld (Job 26:6; Prov 27:20), and is closely associated with death and the grave (Job 28:22; Ps 88:10-12). 2. In the NT, the Hebrew name for the ruler of the Abyss, whose Greek name was Apollyon, “the Destroyer” (Rev 9:11).