power stroke(redirected from power strokes)
Also found in: Medical.
power stroke[′pau̇·ər ‚strōk]
The stroke in an engine during which pressure is applied to the piston by expanding steam or gases.
The stroke in the operating cycle of a reciprocating engine in which both the inlet and the exhaust valves are closed, the fuel-air mixture has been ignited and burned, and the piston is being forced downward by expanding gases. See four-stroke cycle.