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

Then, with the flip of a switch in the control room next door, the cab would start to shake and roll on its piston legs, as if having a seizure. —Burkhard Bilger, New Yorker, 2 Mar. 2026

This is primarily handled by the 4-piston hydraulic disc brakes with 203-mm rotors, which provides some serious stopping power. —Stefan Ionescu march 02, New Atlas, 2 Mar. 2026

But if Cunningham and Duren are the pistons for this car, Thompson is the catalytic converter. —Hunter Patterson, New York Times, 26 Feb. 2026

On Tuesday, piston engine aircraft -- the type that typically use leaded aviation gasoline -- were filled with unleaded fuel now available on site. —Karen Morfitt, CBS News, 17 Feb. 2026

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