n. 跳水者, 潜水者, 活塞

[电] 活柱

Plunger \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. --Knight.

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