plung·er /ˈplʌnʤɚ/
  跳進的人,潛水者,衝入物,活塞
  Plun·ger n.
  1. One who, or that which, plunges; a diver.
  2. A long solid cylinder, used, instead of a piston or bucket, as a forcer in pumps.
  3. One who bets heavily and recklessly on a race; a reckless speculator. [Cant]
  4. Pottery A boiler in which clay is beaten by a wheel to a creamy consistence.
  5. Gun. The firing pin of a breechloader.
  Plunger bucket, a piston, without a valve, in a pump.
  Plunger pole, the pump rod of a pumping engine.
  Plunger pump, a pump, as for water, having a plunger, instead of a piston, to act upon the water. It may be single-acting or double-acting
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  plunger
       n 1: someone who risks losses for the possibility of considerable
            gains [syn: speculator]
       2: someone who dives (into water) [syn: diver]
       3: hand tool consisting of a stick with a rubber suction cup at
          one end; used to clean clogged drains [syn: plumber's
          helper]
       4: mechanical device that has a plunging or thrusting motion
          [syn: piston]