Stroke (engine)

In the context of an internal combustion engine, the term stroke has the following related meanings:

• A phase of the engine's cycle (e.g. compression stroke, exhaust stroke), during which the piston travels from top to bottom or vice versa.
• The type of power cycle used by a piston engine (e.g. two-stroke engine, four-stroke engine).
• "Stroke length", the distance travelled by the piston during each cycle. The stroke length, along with bore diameter, determines the engine's displacement.