\Dash"pot`\, n. (Mach.)
A pneumatic or hydraulic cushion for a falling weight, as in
the valve gear of a steam engine, to prevent shock.
Note: It consists of a chamber, containing air or a liquid,
      in which a piston (a), attached to the weight, falls
      freely until it enters a space (as below the openings,
      b) from which the air or liquid can escape but slowly
      (as through cock c), when its fall is gradually
      checked.
Note: A cataract of an engine is sometimes called a dashpot.