cataclysm

noun

1. any violent upheaval, especially one of a social or political nature.
2. Physical Geography. a sudden and violent physical action producing changes in the earth’s surface.
3. an extensive flood; deluge.

noun

1. a violent upheaval, esp of a political, military, or social nature
2. a disastrous flood; deluge
3. geology another name for catastrophe (def. 4)

n.

1630s, from French cataclysme (16c.), from Latin cataclysmos or directly from Greek kataklysmos “deluge, flood, inundation,” from kataklyzein “to deluge,” from kata “down” (see cata-) + klyzein “to wash,” from PIE *kleue- “to wash, clean” (see cloaca).