jerk(redirected from knee jerk)
Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to knee jerk: Knee jerk reaction, ankle jerk, Knee jerk reflex
The rate of change of acceleration; it is the third derivative of position with respect to time.
A unit of rate of change of acceleration, equal to 1 foot (30.48 centimeters) per second squared per second.