والحركة: وهي الحصول في المكان مسبوقاً بحصوله في مكان آخر
Motion is occupation of a place preceded by occupation of another place.
The key condition is a difference between successive spatial states. If a body occupies position A at one instant and position B at the next, it is described as moving.
This is a metaphysical definition in terms of position and time, not a modern mathematical account of all kinds of motion, velocity, or physical dynamics.