Definition
A jet engine that produces thrust by drawing in air through an inlet, compressing it with a compressor, mixing it with fuel and burning it in a combustion chamber, then expelling the hot, high-velocity exhaust gases out the rear. A turbine in the exhaust path extracts just enough energy from the gas stream to drive the compressor; all remaining energy leaves as a high-speed jet that produces thrust by reaction.
Plain English
An engine that sucks in air, squeezes it, burns fuel in it, and shoots the hot gases out the back. The push from those gases blasting out the back is what moves the airplane forward.
Context Anchor
Seen when comparing turbine engine types, especially turbojet, turbofan, and turboprop engines.
Derivation
Turbo comes from the Latin word for a spinning top or whirl, referring to the spinning turbine inside. Jet refers to the high-speed stream of exhaust gas leaving the rear. Together: an engine that uses a spinning turbine and produces thrust from a jet of exhaust.
Why Pilots Care
Pure turbojets are loud, fuel-hungry, and most efficient at high speeds and high altitudes. Understanding the turbojet is the foundation for understanding every other turbine engine a pilot will fly behind, since turbofans, turboprops, and turboshafts are all variations on this same core.
Intuition Check
Do not read “turbojet” as just any jet-powered engine. A turbojet gets most of its push from the hot exhaust stream itself, not from a propeller or a large front fan.
Example Sentence 1
Early commercial jets like the Boeing 707 used turbojet engines, which were powerful but noisy and inefficient at lower speeds.
Example Sentence 2
At cruise altitude the turbojet engine maintained efficient thrust with minimal compressor surge risk.