'Armageddon' definitions:

Definition of 'Armageddon'

noun

(New Testament) the scene of the final battle between the kings of the Earth at the end of the world

noun

Any catastrophically destructive battle; "they called the first World War an Armageddon"

Armageddon occurs only in Rev. 16:16 (R.V., "Har-Magedon"), as symbolically designating the place where the "battle of that great day of God Almighty" (ver. 14) shall be fought. The word properly means the "mount of Megiddo." It is the scene of the final conflict between Christ and Antichrist. The idea of such a scene was suggested by the Old Testament great battle-field, the plain of Esdraelon (q.v.).