Destruction, the Hebrew name (equivalent to the Greek Apollyon, i.e., destroyer) of "the angel of the bottomless pit" (Revelation 9:11). It is rendered "destruction" in Job 28:22; 31:12; 26:6; Proverbs 15:11; 27:20. In the last three of these passages the Revised Version retains the word "Abaddon." We may regard this word as a personification of the idea of destruction, or as sheol, the realm of the dead.
Source: Easton's Bible Dictionary
Abaddon
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.