peripeteia
/ˌperɪpɪˈtaɪə/noun
- formal a sudden reversal of fortune or change in circumstances, especially in reference to fictional narrative〈正式〉（尤指小说中命运或环境的）突变。
词源
late 16th cent.: from Greek peripeteia 'sudden change', from peri- 'around' + the stem of piptein 'to fall'.