General English


  • noun a solid cylinder that fits into a larger cylinder and moves under fluid pressure, as in petrol and diesel engines or compresses fluids, as in pumps and compressors

Cars & Driving

  • noun the reciprocating element in a reciprocating piston engine


  • A solid cylinder that fits inside a larger cylinder and moves as a result of the power it receives. It can be used to transmit power to or from a connecting rod. Found in reciprocating engines, pumps, and compressors.


  • In a waveguide, a sliding cylinder, usually consisting of a metal or dielectric, which is utilized for tuning. Also called plunger, waveguide plunger, or tuning piston.
  • A cylinder or disk which is fitted closely within a larger cylinder, and which moves against the pressure of a fluid. An example is that in a dashpot.
  • synonymplunger


  • barrel bread

Origin & History of “piston”

The Latin verb pinsere meant ‘beat, pound’. Its past participial stem pist- formed the basis for the noun pistillum ‘grinding stick, pestle’ (from which English gets pistil ‘female flower part’ (18th c.), an allusion to its shape). this passed into Italian as pestello, from which English gets pestle (14th c.). From the Italian stem pest- was formed pestone ‘rammer’, whose variant pistone gave French piston – whence English piston.