pis·​ton | \ˈpi-stən \

Definition of piston 

(Entry 1 of 2)

1 : a sliding piece moved by or moving against fluid pressure which usually consists of a short cylindrical body fitting within a cylindrical chamber or vessel along which it moves back and forth

2 : a sliding valve moving in a cylinder in a brass instrument which when depressed by a finger knob serves to lower the instrument's pitch


biographical name
Pis·​ton | \ˈpi-stən \

Definition of Piston (Entry 2 of 2)

Walter Hamor 1894–1976 American composer

Examples of piston in a Sentence

Recent Examples on the Web: Noun

Like any piston engine, its power diminishes as altitude increases. Eric Tegler, Ars Technica, "One man designed and built the ultimate bush plane," 11 Aug. 2018 That ratio compares the maximum to minimum value of cylinder volume as the piston travels throughout its complete range. Matthew Jancer, Popular Mechanics, "How Infiniti's Variable-Compression Engine Works," 16 July 2018 Because the pistons are horizontally opposed, the boxer engine sits lower in the bay and has less vibration than inline or V-6 set ups. Robert Duffer, chicagotribune.com, "Review: Subaru climbs into 3-row class with 2019 Ascent," 26 June 2018 Atmospheric pressure then pushed the piston down and lifted the payload. Charles R. Morris, WSJ, "‘Energy’ Review: The Path to Power," 21 June 2018 By the very nature of its design, a rotary engine is lighter, less complex, and higher-revving than a typical box of pistons. Blake Z. Rong, Popular Mechanics, "​​The Evolution of the Combustion Engine​​," 5 June 2018 According to museum president Paul Schneider, the Silsby engines used rotary gears instead of pistons, the common feature of the time. Mark Yost, WSJ, "A Museum to Spark New Interest," 11 July 2018 In higher gears, where the stretch from 8000 to 9000 rpm grows to more than a fraction of a second, the churn of its six pistons exactly mimics the characteristic buzz-saw sound of an Airbus A320’s turbofan engines at takeoff. James Lipman, Car and Driver, "2018 Porsche 911 GT3 PDK Automatic," 23 Mar. 2018 His powerful muscles seemed to uncoil, and his shoulders, like oversize pistons, drove us forward, springing over the sand as though a 160-pound man weren’t on his back. Peter Gwin, WSJ, "The Horses That Changed History," 19 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'piston.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of piston


1704, in the meaning defined at sense 1

History and Etymology for piston


French, from Italian pistone, from pistare to pound, from Old Italian, from Medieval Latin, from Latin pistus, past participle of pinsere to crush — more at pestle

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Statistics for piston

Last Updated

28 Nov 2018

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Time Traveler for piston

The first known use of piston was in 1704

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More Definitions for piston



English Language Learners Definition of piston

: a part of an engine that moves up and down inside a tube and that causes other parts of the engine to move


pis·​ton | \ˈpi-stən \

Kids Definition of piston

: a disk or short cylinder that slides back and forth inside a larger cylinder and is moved by steam in steam engines and by the explosion of fuel in automobiles

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More from Merriam-Webster on piston

Rhyming Dictionary: Words that rhyme with piston

Spanish Central: Translation of piston

Nglish: Translation of piston for Spanish Speakers

Comments on piston

What made you want to look up piston? Please tell us where you read or heard it (including the quote, if possible).


a nest or breeding place

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