Abaddon
From Textus Receptus
Abaddon (Hebrew אבדון Avaddon, Greek Apollyon, Latin Exterminans, Coptic Abbaton, meaning "A place of destruction", "The Destroyer", "Depths of Hell") in the Revelation of St. John, is the King of tormenting locusts and the angel of the bottomless pit. (KJV, Rev. 9:1-11).
-- ABAD'DON, n. Heb. Ch. Syr. Sam. to be lost, or destroyed, to perish.
1. The destroyer, or angel of the bottomless pit. Rev. ix.
2. The bottomless pit.
Definition from Webster's American Dictionary of the English Language, 1828.