catastrophe

Any large and disastrous event of great significance.

The Chernobyl disaster was a catastrophe.

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.

A disaster beyond expectations.

The dramatic event that initiates the resolution of the plot; the dénouement.

Pat : he comes like the Cataſtrophe of the old Comedie : my Cue is villanous Melancholly, with a ſighe like Tom o’ Bedlam.

A type of bifurcation, where a system shifts between two stable states.