piston

noun

pis·​ton ˈpi-stən 

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

Examples of piston in a Sentence

Recent Examples on the Web

As the piston rises again, compression of the fuel and air happens as the vacuum created underneath the cylinder pulls in another batch of fuel and air. —New Atlas, 14 June 2025

Under the hood is a 2.7-liter inline six-cylinder making 200 horsepower, which has upgraded pistons, camshafts, and a cylinder head. —Erik Shilling, Robb Report, 12 May 2025

Inside, 16 relatively small pistons (92 mm) fire off in a magnificent short-stroke (78.55 mm) scream at 9,000 rpm. —New Atlas, 28 Apr. 2025

Last week Cirrus Aircraft announced the introduction of a new addition to its SR series of single-engine piston aircraft, the G7+, which will feature the company’s Safe Return Emergency Autoland technology as standard equipment. —Jim Vinoski, Forbes.com, 22 May 2025

Word History

Etymology

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

First Known Use

1704, in the meaning defined at sense 1

Phrases Containing piston

• piston pin
• piston ring
• piston rod

Kids Definition

piston

noun

pis·​ton ˈpis-tən 

: a sliding piece moved by or moving against the pressure of a fluid (as steam or hot gases) that usually consists of a short solid cylinder moving within a larger hollow cylinder

Biographical Definition

Piston

biographical name

Pis·​ton ˈpi-stən 

Walter Hamor 1894–1976 American composer