piston

[ pis-tuh n ]
/ ˈpɪs tən /

noun

a 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.

Origin of piston

1695–1705; < French < 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

OTHER WORDS FROM piston

pis·ton·like, adjective sub·pis·ton, noun

Definition for piston (2 of 2)

Piston
[ pis-tuh n ]
/ ˈpɪs tən /

noun

Walter,1894–1976, U.S. composer.

Example sentences from the Web for piston

British Dictionary definitions for piston

piston
/ (ˈpɪstən) /

noun

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

Word Origin for piston

C18: via French from Old Italian pistone, from pistare to pound, grind, from Latin pinsere to crush, beat

Scientific definitions for piston

piston
[ pĭstən ]

A solid cylinder or disk that fits snugly into a hollow cylinder and moves back and forth under the pressure of a fluid (typically a hot gas formed by combustion, as in many engines), or moves or compresses a fluid, as in a pump or compressor.