catastrophe

noun

1. a sudden and widespread disaster: the catastrophe of war.
2. any misfortune, mishap, or failure; fiasco: The play was so poor our whole evening was a catastrophe.
3. a final event or conclusion, usually an unfortunate one; a disastrous end: the great catastrophe of the Old South at Appomattox.
4. (in a drama) the point at which the circumstances overcome the central motive, introducing the close or conclusion; dénouement.Compare catastasis, epitasis, protasis.
5. Geology. a sudden, violent disturbance, especially of a part of the surface of the earth; cataclysm.
6. Also called catastrophe function. Mathematics. any of the mathematical functions that describe the discontinuities that are treated in catastrophe theory.

noun

1. a sudden, extensive, or notable disaster or misfortune
2. the denouement of a play, esp a classical tragedy
3. a final decisive event, usually causing a disastrous end
4. Also called: cataclysm any sudden and violent change in the earth’s surface caused by flooding, earthquake, or some other rapid process

n.

1530s, “reversal of what is expected” (especially a fatal turning point in a drama), from Latin catastropha, from Greek katastrophe “an overturning; a sudden end,” from katastrephein “to overturn, turn down, trample on; to come to an end,” from kata “down” (see cata-) + strephein “turn” (see strophe). Extension to “sudden disaster” is first recorded 1748.