a cataclysmic event
(the Apocalypse)
the ultimate destruction of the world, as depicted in the Book of Revelation in the Bible
the Book of Revelation
something viewed as a prophetic revelation
any of a number of early Jewish and Christian works that describe the future establishment of God's kingdom
[Middle English in the sense ‘revelation’, via late Latin from Greek apokalyptein to uncover, from apo- + kalyptein to cover]