A supercharger (also known as a blower) is an air compressor used to force more air (and hence more oxygen) into the combustion chamber(s) of an internal combustion engine than can be achieved at ambient atmospheric pressure (natural aspiration).
The additional mass of oxygen-containing air that is forced into the engine improves on its volumetric efficiency which allows it to burn more fuel in a given cycle—which in turn makes it produce more power. A supercharger can be powered mechanically by belt, gear and shaft, or chain-drive from the engine's crankshaft. It can also be driven by a gas turbine powered by the exhaust gases from the engine. Turbine-driven superchargers are correctly referred to as turbo-superchargers—or more commonly as turbochargers.