n.
A sudden change of events or reversal of circumstances, especially in a literary work.
[Greek, from peripiptein, peripet-, to change suddenly : peri-, peri- + piptein, to fall.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.