from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A solid cylinder or disk that fits snugly into a larger cylinder and moves under fluid pressure, as in a reciprocating engine, or displaces or compresses fluids, as in pumps and compressors.
  • noun Music A valve mechanism in brass instruments for altering the pitch.

from The Century Dictionary.

  • noun In machinery, a movable piece, generally of a cylindrical form, so fitted as to fill the sectional area of a tube, such as the barrel of a pump or the cylinder of a steam-engine, and capable of being driven alternately in two directions by pressure on one or the other of its sides.
  • noun In musical wind-instruments of the trumpet family, one of the forms of valve whereby a crook is temporarily added to the tube and the pitch of the tones altered.
  • noun In organ-building, a thumb-knob which may be pushed in like a piston, whereby some change in registration is pneumatically effected; a pneumatic coupler or combination knob.
  • noun The central retractile part of the acetabulum or sucker of a cephalopod, whose action in producing a vacuum resembles that of the piston of an air-pump.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Mach.) A sliding piece which either is moved by, or moves against, fluid pressure. It usually consists of a short cylinder fitting within a cylindrical vessel along which it moves, back and forth. It is used in steam engines to receive motion from the steam, and in pumps to transmit motion to a fluid; also for other purposes.
  • noun (Steam Eng.) that part of a piston which is made fast to the piston rod.
  • noun a rod by which a piston is moved, or by which it communicates motion.
  • noun (Steam Eng.) a slide valve, consisting of a piston, or connected pistons, working in a cylindrical case which is provided with ports that are traversed by the valve.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A solid disk or cylinder that fits inside a hollow cylinder, and moves under pressure (as in an engine) or displaces fluid (as in a pump)
  • noun music A valve device in some brass instruments for changing the pitch

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun United States neoclassical composer (1894-1976)
  • noun mechanical device that has a plunging or thrusting motion


from The American Heritage® Dictionary of the English Language, 4th Edition

[French, from Italian pistone, pestone, large pestle, from pestare, to pound, crush, from Late Latin pistāre, frequentative of Latin pīnsere, pīnsāre.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From French piston.


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  • But Black has size on his side and keeps forcing him against the ropes, getting in short piston blows into his ribs, which seem to move with a life of their own after the first blow.

    Joshua Samuel Brown josambro 2010

  • (enquiry) bears upon the face of it the stopping (istanai) of the stream; and the word piston (faithful) certainly indicates cessation of motion; then, again, mneme (memory), as any one may see, expresses rest in the soul, and not motion.

    Cratylus 427? BC-347? BC Plato 1855

  • The type IV secretory system is an elaboration of the type II, except now the piston is a long filament, and that filament can stick to surfaces.

    The Politically Incorrect Guide to Darwinism and Intelligent Design Review: IC is not nice (Chapter 10) - The Panda's Thumb 2006

  • The type IV secretory system is an elaboration of the type II, except now the piston is a long filament, and that filament can stick to surfaces.

    What is this thing called Science? - The Panda's Thumb 2005

  • One part of the piston is a centrifugal piston which functions as a striking piston, whereas the other part is used for the transmission of drilling rods and compression air in order to blow clean the drilling hole.

    7.1 Pneumatic jack hammer, drilling stand, jackleg 1993

  • That style of machine for moulding candles in which the candles are forced out at the top by means of a piston is the one most employed, and it is an apparatus of this kind that we illustrate herewith.

    Scientific American Supplement, No. 611, September 17, 1887 Various

  • The piston, which is very long, rubs at its upper end against the sides of the cylinder, C.

    Scientific American Supplement, No. 623, December 10, 1887 Various

  • As, however, the piston is the only movable part, the force of the steam is directed to that part, and the motion is then transmitted to the crank, and to the shaft of the engine.

    Practical Mechanics for Boys J. S. Zerbe

  • The piston is a single casting unusually long and light, and is packed with four spring rings of 3/8 inch square brass wire.

    Mechanical Drawing Self-Taught Joshua Rose

  • "Johnson's right upper-cut is described as the piston of an ocean greyhound making twenty-seven knots," said the man, taking no notice of the answer, and speaking in awestruck tones.

    Essays in Rebellion Henry W. Nevinson 1900


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