catastrophe
/kəˈtæstrəfɪ/noun
1- an event causing great and often sudden damage or suffering; a disaster（常突如其来的）大灾难; 大灾祸：
an environmental catastrophe
环境大灾难
mass noun leading the world to catastrophe.将世界引入劫难。
1.1
- the denouement of a drama, especially a classical tragedy（尤指古典悲剧的）结局。
词源
mid 16th cent. （in the sense 'denouement'）： from Latin catastropha, from Greek katastrophē 'overturning, sudden turn', from kata- 'down' + strophē 'turning' （from strephein 'to turn'）.