Definition
An aircraft engine that uses a gas turbine to drive a propeller through a reduction gearbox. The turbine extracts energy from the hot, expanding gases produced by burning fuel and uses most of that energy to spin the propeller, which produces the majority of the thrust. A small amount of residual thrust comes from the exhaust gases.
Plain English
It's a jet engine that, instead of pushing the aircraft forward with its exhaust, uses the spinning power inside the engine to turn a propeller. The propeller does almost all the work of moving the airplane.
Context Anchor
Seen in discussions of propeller control, engine failure, shutdown, and feathering on turbine-powered propeller airplanes.
Derivation
Turbo' comes from the Latin 'turbo,' meaning a spinning top or whirl, referring to the turbine wheels inside the engine. 'Prop' is short for propeller. So a turboprop is literally a turbine-driven propeller engine — the turbine spins, and that spinning turns the prop.
Why Pilots Care
Turboprop engines give reliable power, good fuel efficiency at lower speeds, and strong short-field performance for many training and commuter airplanes.
Intuition Check
A turboprop is not simply a piston engine with a propeller, and it is not a pure jet engine. It is a turbine engine whose main job is to turn a propeller.
Example Sentence 1
After engine failure on the turboprop, the pilot feathered the propeller to reduce drag.
Example Sentence 2
After an engine failure the crew shut down the turboprop engine and feathered the propeller to reduce drag.