Definition
A rotating set of angled blades, driven by the engine, that converts engine power into thrust by accelerating a mass of air rearward. Each blade acts as a small rotating wing, generating aerodynamic force as it moves through the air.
Plain English
The spinning blades on the front (or back) of many small aircraft. The engine turns them, and they pull or push the aircraft through the air.
Context Anchor
Seen in aircraft equipment descriptions, checklists, maintenance notes, and pilot reports when referring to the aircraft’s propeller.
Derivation
From the Latin propellere, meaning 'to drive forward' (pro- 'forward' + pellere 'to push'). The propeller is literally the device that drives the aircraft forward.
Why Pilots Care
Propeller condition, pitch, and diameter affect takeoff distance, climb performance, cruise efficiency, and overall safety margins.
Intuition Check
Do not confuse the PROP with the engine. The engine supplies the power; the PROP is the rotating blade assembly that uses that power to move air and produce thrust.
Example Sentence 1
Before starting the engine, the pilot called 'clear prop!' to warn anyone nearby.
Example Sentence 2
A constant-speed propeller lets the pilot maintain the most efficient engine RPM throughout the climb and cruise.