Machinery. a pistonlike reciprocating part moving within the cylinder of a pump or hydraulic device.
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.
a reckless bettor or speculator.