catastrophe

Etymology

From Ancient Greek καταστροφή (katastrophḗ), from καταστρέφω (katastréphō, “I overturn”), from κατά (katá, “down, against”) + στρέφω (stréphō, “I turn”).

noun

1. Any large and disastrous event of great significance.
   Last night, after the brief sitting of the House of Lords, and before catastrophe befell the Government in the Commons, I had a long chat with the Premier, in which he discussed the Home Rule question and his relations with it in perfectly frank manner. 1896, Henry W[illiam] Lucy, “[Session 1894.] A Bad Beginning.”, in A Diary of the Home Rule Parliament, 1892-1895, London, Paris, Melbourne, Vic.: Cassell and Company, Limited, page 320
   Between these high lights accumulated disaster, social catastrophe. 1913, H. G. Wells, “The New Source of Energy”, in The World Set Free, New York: E. P. Dutton & Company, pages 54–55
   Am I not a man? And is a man not stupid? I'm a man, so I married. Wife, children, house, everything. The full catastrophe. 1964, Nikos Kazantzakis, Michael Cacoyannis, Zorba the Greek, spoken by Alexis Zorba (Anthony Quinn)
2. (insurance) A disaster beyond expectations.
3. (narratology) The dramatic event that initiates the resolution of the plot; the dénouement.
4. (mathematics) A type of bifurcation, where a system shifts between two stable states.