A portable machine variously constructed, for exerting great
   pressure, or lifting or moving a heavy body through a small distance.
   It consists of a lever, screw, rack and pinion, hydraulic press, or any
   simple combination of mechanical powers, working in a compact pedestal
   or support and operated by a lever, crank, capstan bar, etc. The name
   is often given to a jackscrew, which is a kind of jack.