Strong’s Greek
G3 — Abaddon
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
Ἀβαδδών
Abaddon — pronounced ab-ad-dohn'
of Hebrew origin (11); a destroying angel:--Abaddon. see HEBREW for 011
1 occurrence in the KJV.
Revelation 9:11
And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.