pis·​ton | \ ˈpi-stən How to pronounce piston (audio) \

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 How to pronounce Piston (audio) \

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

That can cause abnormal combustion and damage pistons and connecting rods. Tom Krisher, The Seattle Times, "Hyundai finds new engine problem, prompting another recall," 30 Mar. 2019 The Korean automaker, under pressure from safety regulators, is recalling about 20,000 Veloster cars in the U.S. and Canada because fuel can prematurely ignite in the cylinders around the pistons. Tom Krisher, The Seattle Times, "Hyundai finds new engine problem, prompting another recall," 30 Mar. 2019 Instead of using shims or lubricants to decouple the pad from the caliper, stick the backing plate to the piston or caliper housing, effectively making its mass far larger. Mike Allen, Popular Mechanics, "How to Fix Squeaky Brakes," 14 Mar. 2019 Suddenly, its piston engine blew, throwing two connecting rods. Eric Tegler, Ars Technica, "One man designed and built the ultimate bush plane," 11 Aug. 2018 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

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

16 May 2019

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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 How to pronounce piston (audio) \

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 strong desire or propensity

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