I think 'deceleration' is more ambiguous. I tend to think of derivatives taken with respect to time in terms of high school physics. Let x = postion x' = vel

I think 'deceleration' is more ambiguous. I tend to think of derivatives taken with respect to time in terms of high school physics. Let x = postion x' = velocity x'' = acceleration x''' = jerk (and, incidentally, the 4th through 6th derivatives of position are known, respectively, as 'snap', 'crackle', and 'pop' ;-))