Plain English Meaning

An engine that uses its own exhaust to pump extra air in, so it can keep making strong power high up where the air is thin.

Full Definition

A reciprocating aircraft engine fitted with a turbocharger — a device that uses the engine's exhaust gases to drive a turbine, which in turn spins a compressor that forces additional air into the engine's induction system. This compressed air allows the engine to maintain sea-level (or higher) manifold pressure at altitudes where a normally aspirated engine would lose power due to thinning air.