Catastrophe

(kãtæ-strõfi)
1. The change which produces the final event of a dramatic piece; the dénouement.
2. ‘A final event; a conclusion generally unhappy’ (J.); overthrow, ruin 1601.
3. An event producing a subversion of the order or system of things 1696. esp in Geol.
A sudden and violent physical change, such as an upheaval, depression, etc (See CATACYLSM, CATASTROPHISM.) 1882.
4. A sudden disaster. (Used very loosely.) 1748.