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The rate of change of acceleration is jerk.i.e., the derivative of acceleration with respect to time.

Jerk is a vector, and there is no generally used term to describe its scalar magnitude  

The SI units of jerk are metres per second cubed    

If acceleration can be felt by a body as the force (hence pressure) exerted by the object bringing about the acceleration on the body, jerk can be felt as the change in this pressure. For example a passenger in an accelerating vehicle with zero jerk will feel a constant force from the seat on his or her body; whereas positive jerk will be felt as increasing force on the body, and negative jerk as decreasing force on the body.

Jerk is often used in engineering, especially when building roller coasters.  Jerk may be considered when the excitation of vibrations is a concern. A device that measures jerk is called a "jerkmeter".

Jerk is also important to consider in manufacturing processes. Rapid changes in acceleration of a cutting tool can lead to premature tool wear and result in uneven cuts. This is why modern motion controllers include jerk limitation features.

In mechanical engineering, jerk is considered, in addition to velocity and acceleration, in the development of cam profiles because of  tribological  implications and the ability of the actuated body to follow the cam profile without chatter.