piston
n. countablen. a part of an engine or pump that moves up and down inside a tube. It pushes against air or liquid to create power or movement.
n. a sliding component, typically a solid cylinder, that moves back and forth within a hollow cylinder against fluid pressure. In brass instruments, it refers to the valve mechanism used to alter the length of the air column.
The engine has four pistons moving at high speed.
The mechanic explained that the damaged piston was preventing the engine from generating enough power to accelerate.
In a reciprocating internal combustion engine, the piston transfers the force of expanding gas in the cylinder to the crankshaft via a connecting rod, converting thermal energy into mechanical work.
Commonly used in mechanical engineering and music (brass instruments).
Last updated May 6, 2026