Changes in position over time is motion, and the rate of change may be velocity or speed.
A person walking is an example of a change in position over time.
Speed --- actually, if your question is 'position' over time, there is no answer since position is a vector quantity. And position divided by time will still yield a vector quantity-- velocity. If the question asks for change in distance over time, then the answer is speed. --gh ---
velocity
The answer is displacement.
motion
Velocity is the rate of change of position over time.
movement
movement
motion
In the question, "an object's change in position...over...time" is a perfectly reasonable definition of velocity.
Changes in position over time is motion, and the rate of change may be velocity or speed.
Assuming position is on the y axis and time is on the x axis, a positive slope means the position has increased over time.