definition of
cataclysm

[1] #1 cataclysm n. [catastrophe] a sudden violent change in the earth's surface. wn

[2] #2 cataclysm n. [calamity, catastrophe, disaster, tragedy] an event resulting in great loss and misfortune; "the whole city was affected by the irremediable calamity"; "the earthquake was a disaster". wn