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

Braking is handled by Brembo, with 320 mm dual discs up front and a 260 mm single disc with a dual-piston caliper at the rear. —New Atlas, 9 Dec. 2025

The to-scale model car has a V6 engine with moving pistons, independent suspension on all four wheels, and actual steering capabilities. —Mia Huelsbeck, PEOPLE, 30 Nov. 2025

This created enough of a temperature gap to activate the piston and spin the flywheel. —Aamir Khollam, Interesting Engineering, 13 Nov. 2025

Idling your engine could damage your engine's pistons, decrease your car's fuel efficiency and hurt the environment, according to Firestone. —Jalen Williams, Freep.com, 10 Nov. 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