What is the term for the total volume swept by the pistons in an engine?

The total volume swept by an engine’s pistons is called displacement.

Engine displacement measures the combined volume traveled by all pistons inside their cylinders. In a conventional reciprocating engine, it is calculated from the cylinder bore, piston stroke, and number of cylinders. Manufacturers usually express it in cubic centimetres, liters, or cubic inches.

Displacement is not the same as bore or stroke. Bore is the diameter of a cylinder, while stroke is the distance a piston travels between its upper and lower positions. Compression ratio compares cylinder volume before compression with the much smaller volume remaining when the piston reaches the top.

Displacement often gives a rough clue about an engine’s potential torque and fuel consumption, but it does not determine power by itself. Turbocharging, engine speed, valve timing, compression, fuel delivery, and efficiency can allow a smaller engine to outperform a larger naturally aspirated one.