Definition
The rearmost section of a turbine engine's exhaust system, shaped to control the velocity and pressure of the gases leaving the engine. By varying its cross-sectional area, the exhaust nozzle converts the pressure energy of the hot exhaust gases into high-velocity flow, producing thrust as the gases exit.
Plain English
The opening at the back of a jet engine that the hot gases blast out of. Its shape speeds the gases up so they push the aircraft forward.
Context Anchor
Seen in engine descriptions, turbine engine operation, and aircraft maintenance discussions involving the exhaust system.
Derivation
From Latin 'nasus' (nose), via Old French, giving 'nozzle' as a small spout or projecting outlet. Combined with 'exhaust' (the spent gases leaving the engine), it simply names the spout the burned gases shoot out of.
Why Pilots Care
Nozzle shape and size directly control thrust, engine efficiency, and fuel burn.
Analogy
Think of putting your thumb over the end of a garden hose. The water has the same pressure behind it, but narrowing the opening makes it shoot out faster. The exhaust nozzle does the same thing with hot engine gases.
Intuition Check
Do not think of an exhaust nozzle as just a simple pipe ending. In many aircraft engines, especially turbine engines, its shape is part of how the engine controls and uses the exiting gases.
Example Sentence 1
During the walkaround, the pilot inspected the exhaust nozzle for cracks and signs of overheating.
Example Sentence 2
Variable exhaust nozzles open wider during afterburner use to handle higher gas flow.