noun

1. any of various Jewish and Christian pseudonymous writings (c. 200 -c. 300) depicting symbolically the ultimate destruction of evil and triumph of good
2. a disclosure regarded as prophetic; revelation
3. a cataclysmic event, esp. the sudden and violent end of the world
4. the last book of the New Testament; Revelation

Etymology: LL(Ec) apocalypsis < Gr apokalypsis < apokalyptein, to disclose < apo-, from + kalyptein, to cover < IE base *el- > hall