The units of jerk are metres per a second cubed (m.s-4). There is no universal agreement on the symbol for jerk, but j is commonly used.
Jerk is used at times in engineering. Some fragile or precision objects can be safely subjected not only to a maximum acceleration, but also a maximum jerk.
Higher derivatives of velocity than jerk also exist, but they are rarely necessary, and hence lack agreed upon names, although many suggestions have been made.