propeller propeller /prəˈpel.ər/ aep /-ɚ/ noun [C] (INFORMALprop) ► F0 a device that causes a ship or aircraft to move, consisting of two or more blades that turn round at high speedSee picture: propeller Thesaurus+: ↑Parts of ships and boatsThesaurus+: ↑Parts of aeroplanes