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.
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 person or thing that plunges.
a reckless bettor or speculator.

Origin of plunger

First recorded in 1605–15; plunge + -er1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for plunger

Contemporary Examples of plunger

  • You can draw the plunger up and down and it looks as if the blood is mixing with the liquid.

    The Daily Beast logo
    13 Movie Tricks…Revealed!

    Marlow Stern

    October 31, 2010

  • Trying to pull the plunger back would snap the ring and effectively break the syringe.

    The Daily Beast logo
    How to Save a Million Lives

    Joshua Robinson

    October 13, 2010

Historical Examples of plunger

British Dictionary definitions for plunger



a rubber suction cup fixed to the end of a rod, used to clear blocked drains
a device or part of a machine that has a plunging or thrusting motion; piston
informal a reckless gambler
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for plunger

1610s, "one who plunges," agent noun from plunge (v.). As a mechanism, 1777.

Online Etymology Dictionary, © 2010 Douglas Harper