armageddon
n. C / Un. a final and total war or a huge disaster that destroys the world.
n. the site or occasion of a final, decisive battle between the forces of good and evil; by extension, any catastrophic conflict or disaster that threatens total destruction.
Some people fear that a nuclear war would lead to armageddon.
Environmentalists warn that failing to address climate change could result in an ecological armageddon for future generations.
The film depicts a post-apocalyptic landscape where survivors of a global armageddon struggle to rebuild society amidst the ruins of the old world.
From Middle English Hermagedon, from Old English Ermagedon, from Latin Hermagedon, from Ancient Greek Ἁρμαγεδών (Harmagedṓn), used in Revelation 16:16, referring to Mount Megiddo, the place of the last battle at the Last Judgment; from Hebrew הר מגידו / הַר מְגִדּוֹ (har megiddo).
Often used with the definite article ('the armageddon') when referring to the biblical event, but used as a common noun for general catastrophes.