A supercharger is a device that forces air into the engine to enhance performance.
It operates in a very similar way to a turbocharger, and in fact a turbocharger is actually a form of supercharger (and used to be called a turbosupercharger).
The term “supercharger” in modern automotive use is generally accepted to refer to a supercharger that is mechanically driven (by a belt, chain, gear etc.) unlike turbos which are driven by air flow.
Like a turbo, superchargers are usually bolted to the side of the engine and operate by forcing compressed air into the engine. Compressed air allows the engine to generate more power.
Like turbochargers, superchargers assist the engine in creating more power and torque (turning power) Superchargers have one big advantage over turbochargers which is that they deliver compressed air to the engine almost immediately meaning that there is no lag in power delivery like there can be in a turbo-powered engine