Plain English Meaning

Engines that use their own exhaust to push extra air into the cylinders, so they keep producing strong power even when flying high where the air is thin.

Full Definition

Aircraft piston engines fitted with a turbocharger — a device that uses energy from the engine's exhaust gases to spin a turbine, which drives a compressor that forces additional air into the engine's intake. By packing more air into the cylinders, the engine can burn more fuel and maintain rated power at altitudes where a normally aspirated engine would lose power due to air.