motion
noun[L. motio. See Vove.]
The act or process of changing place; change of local position; the passing of a body from one place to another; change of distance between bodies; opposed to rest. Animal motion is that which is performed by animals in consequence of volition or an act of the will; but how the will operates on the body in producing motion, we cannot explain. Mechanical motion is effected by the force or power of one body acting on another. Perpetual motion is that which is effected or supplied by itself, without the impulse or intervention of any external cause. Hitherto it has been found impossible to invent a machine that has this principle.