1. a rubber suction cup fixed to the end of a rod, used to clear blocked drains
2. a device or part of a machine that has a plunging or thrusting motion; piston
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
(also ram), a piston that has a smooth generatrix (generating surface) or annular grooves and is substantially longer than it is wide. Plungers are chiefly used in hydraulic machines, where they serve as components of pumps, of hydraulic presses and lifts, of slide valves in hydraulic drives, and of multistage gas compressors.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
A wooden shaft with a large rubber suction cup at the end, used to clear plumbing traps and waste outlets.
The long rod or piston of a reciprocating pump.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
plumber’s friend, force cup, plumber’s helper, plunger
A tool consisting of a rubber suction cup attached to a handle; set over a plumbing trap (or the like) and worked with a pumping action to clear the trap of minor obstructions.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.