cataclysm

 
Pronunciation: /ˈkatəˌklɪz(ə)m/

noun

  • a large-scale and violent event in the natural world: the cataclysm at the end of the Cretaceous Period
  • a sudden violent political or social upheaval: the cataclysm of the First World War

Origin:

early 17th century (originally denoting the biblical Flood described in Genesis): from French cataclysme, via Latin from Greek kataklusmos 'deluge', from kata- 'down' + kluzein 'to wash'