Recent exciting work on Cavendish’s natural philosophy highlights the important role of motion in her system. But what is motion, according to Cavendish? I argue that motion, for Cavendish, is what I call ‘compositional motion’: for a body to be in motion is just for it to divide from some matter and join with other matter. So when Cavendish claims to reduce all natural change to motion, she is really reducing all natural change to mereological change. Cavendish also uses ‘motion’ to name the power that matter has to set itself in compositional motion. That power is not reducible to local motion. If motion is not local motion and if motive power is not a function of actual motion, then despite her polemics, Cavendish does not reduce natural change to local motion. Instead, she offers a unique and exciting account of natural change.