Definition
A turbojet is a type of jet engine that produces thrust by drawing in air, compressing it with a rotating compressor, mixing it with fuel and burning it in a combustion chamber, then expelling the hot, high-velocity exhaust gases rearward through a turbine and nozzle. The turbine extracts just enough energy from the exhaust to drive the compressor; the remaining energy leaves as a high-speed jet, which produces the forward thrust.
Plain English
A turbojet is a jet engine that sucks in air, squeezes it, burns fuel in it, and shoots the hot gases out the back to push the aircraft forward. All of the thrust comes from that fast-moving exhaust.
Context Anchor
Seen in takeoff performance discussions when comparing how different types of aircraft engines affect runway distance, acceleration, and climb after takeoff.
Derivation
"Turbo" comes from the Latin turbo, meaning a spinning or whirling thing -- a reference to the rotating turbine and compressor inside the engine. "Jet" refers to the high-speed stream of exhaust gas shot out the back. So the name simply describes what the engine is: a spinning machine that produces a jet.
Why Pilots Care
Turbojets behave very differently from piston engines on takeoff and climb. They produce relatively low thrust at low airspeeds and need longer takeoff rolls, but become more efficient at high altitudes and high speeds. Knowing the engine type tells a pilot what to expect from the performance charts.
Intuition Check
Do not confuse turbo jet with a propeller airplane that has a turbocharger. A turbo jet makes its main thrust from high-speed exhaust, not from a propeller.
Example Sentence 1
Because the airliner is powered by turbojet engines, it requires a long runway and accelerates more gradually on the takeoff roll than a propeller-driven aircraft.
Example Sentence 2
At high altitude the turbo jet continued to produce thrust even though the air was thinner.