a disc or cylindrical part that slides to and fro in a hollow cylinder. In an internal-combustion engine it is forced to move by the expanding gases in the cylinder head and is attached by a pivoted connecting rod to a crankshaft or flywheel, thus converting reciprocating motion into rotation
WordReference Random House Learner's Dictionary of American English © 2026
pis•ton /ˈpɪstən/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2026- Mechanical Engineeringa disk or solid, pipe-shaped piece moving within a longer tube and putting pressure on, or receiving pressure from, a fluid or gas:When the gas mixture explodes it forces the piston down, and this motion is transferred to the car's wheels.
- a pumplike valve used to change the pitch in a cornet, trumpet, or the like.
pis•ton
(pis′tən),USA pronunciation n.
pis′ton•like′, adj.
Pis•ton (pis′tən),USA pronunciation n.
- Mechanical Engineeringa disk or cylindrical part tightly fitting and moving within a cylinder, either to compress or move a fluid collected in the cylinder, as air or water, or to transform energy imparted by a fluid entering or expanding inside the cylinder, as compressed air, explosive gases, or steam, into a rectilinear motion usually transformed into rotary motion by means of a connecting rod.
- a pumplike valve used to change the pitch in a cornet or the like.
- Italian pistone piston, a learned alteration of pestone large pestle, equivalent. to pest(are) to pound (variant of Medieval Latin pistare, derivative of Latin pīstus past participle of pīnsere to pound) + -one augmentative suffix
- French
- 1695–1705
Pis•ton (pis′tən),USA pronunciation n.
- Biographical Walter, 1894–1976, U.S. composer.
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