peripeteia (n.)

also peripetia, "that part of a drama in which the plot is tied together and the whole concludes, the denouement," 1590s, from Greek peripeteia "a turn right about; a sudden change" (of fortune, in a tragedy), from peri "around" (see peri-) + stem of piptein "to fall," from PIE *pi-pt-, reduplicated form of root *pet- "to rush; to fly."