Supercharger is an air compressor that increases the pressure or density of air supplied to an internal combustion engine. This gives each intake cycle of the engine more oxygen, letting it burn more fuel thus increasing power.
Power to drive the supercharger is provided mechanically by means of a belt, gear, shaft, or chain connected to the engine's crankshaft.
When a supercharger is powered by a turbine powered by exhaust gas, it is known as a turbocharger or simply a turbo.