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

Powered by a piston engine running on standard fuel, the drone was praised for its simple construction, reliability, and low cost. —Bojan Stojkovski, Interesting Engineering, 2 Nov. 2025

Elsewhere, the e-cargo is built around aluminum front and rear frame components, rolls on 20-inch wheels wearing Scwhalbe rubber, and comes to a halt courtesy of Tektro quad-piston hydraulic brakes rocking 180-mm discs. —New Atlas, 31 Oct. 2025

This includes the engine’s cylinder heads, valves, pistons, fuel system pipes, machine gun components, fuselage, the wings and the cockpit panel pieces, according to the BBC. —Charna Flam, PEOPLE, 29 Oct. 2025

Among the modifications performed by Koenig were upgraded camshafts, pistons, and exhaust, which added 110 brake horsepower to the output of the V-12. —Erik Shilling, Robb Report, 21 Oct. 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