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

Its boosted flat-six engine receives a power bump, and rear-axle steering is now standard, as are larger brakes with six-piston calipers up front. — Bradley Iger, Robb Report, 16 Oct. 2026

During a downward stroke, a valve expands against the chamber walls, forming a seal and acting like a piston to force venom towards the exit. — Mike McRae 12, New Atlas, 13 Oct. 2026

His steam turbine could generate power far more cheaply, and on a vastly greater scale, than traditional piston engines. — Chang Che, New Yorker, 24 Sep. 2026

There’s also a new lubrication system, forged pistons and rods, and revised exhaust manifolds that ensure durability in extended high-load, high-temperature environments. — Jerry Perez, The Drive, 3 Sep. 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

Rhymes for piston

• cystine

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