Don't be a $\frac{d^3x}{dt^3}$

What does it all mean?
Don't be a $\frac{d^3x}{dt^3}$

What does it all mean?
It means don't be a jerk. The third derivative of position (i.e. the change in acceleration) is called "jerk", though it's a little used quantity. It's called jerk because a changing acceleration is felt as a "jerk" in that direction.