Armageddon

[ahr-muh-ged-n] /ˌɑr məˈgɛd n/
noun
1.
the place where the final battle will be fought between the forces of good and evil (probably so called in reference to the battlefield of Megiddo. Rev. 16:16).
2.
the last and completely destructive battle:
The arms race can lead to Armageddon.
3.
any great and crucial conflict.
British Dictionary definitions for Armageddon

Armageddon

/ˌɑːməˈɡɛdən/
noun
1.
(New Testament) the final battle at the end of the world between the forces of good and evil, God against the kings of the earth (Revelation 16:16)
2.
a catastrophic and extremely destructive conflict, esp World War I viewed as this
Word Origin
C19: from Late Latin Armagedōn, from Greek, from Hebrew har megiddōn, mountain district of Megiddo, in N Palestine, site of various battles in the Old Testament
Word Origin and History for Armageddon
n.

"a final conflict," 1811, figurative use of name in Rev. xvi:16, place of the great and final conflict, from Hebrew Har Megiddon "Mount of Megiddo," city in central Palestine, site of important Israeli battles.

Armageddon in Culture
Armageddon [(ahr-muh-ged-n)]

In the Book of Revelation, the site of the final and conclusive battle between good and evil, involving “the kings of the Earth and the whole world,” on the “great day of God Almighty.”

Note: Figuratively, “Armageddon” is any great battle or destructive confrontation.
Armageddon in the Bible

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.).