King James Bible
King James Version (KJV)

Of Hebrew origin ('abaddown); a destroying angel -- Abaddon.
see HEBREW 'abaddown
1. ruin, destruction (from אָבַד to perish), Job 31:12.
2. the place of destruction equivalent to Orcus, joined with שְׁאול, Job 26:6; Proverbs 15:11.
3. as a proper name it is given to the angel-prince of the infernal regions, the minister of death and author of havoc on earth, and is rendered in Greek by Ἀπολλύων Destroyer, Revelation 11:11.