A turbocharger, or turbo, is a gas compressor. It is used to force air into an internal combustion engine. A turbocharger is a form of forced induction. It increases the amount of air entering the engine to create more power. A turbocharger has the compressor powered by a turbine. The turbine is driven by the exhaust gas from the engine. It does not use a direct mechanical drive. This helps to improve the performance of the turbocharger. Early builders of turbochargers called them as "turbosuperchargers".
http://www.tenghengturbo.com/turbocharger/