[pluhn-jer] 
| 1. | Machinery. a pistonlike reciprocating part moving within the cylinder of a pump or hydraulic device. |
| 2. | Automotive. a pistonlike part in the valve of a pneumatic tire. |
| 3. | Also called force cup, plumber's friend, plumber's helper. a device consisting of a handle with a rubber suction cup at one end, used as a force pump to free clogged drains and toilet traps. |
| 4. | a person or thing that plunges. |
| 5. | a reckless bettor or speculator. |
