(wĭp′stôl′, hwĭp′-)
A usually intentional stall in which a small aircraft enters a vertical climb, pauses, slips backward momentarily, then drops nose downward.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Aeronautics) a stall in which an aircraft goes into a nearly vertical climb, pauses, slips backwards momentarily, and drops suddenly with its nose down
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈʰwɪpˌstɔl, ˈwɪp-)
a stall during a vertical climb of an aircraft in which the nose falls forward and downward in a whiplike movement.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.