From Longman Dictionary of Contemporary Englishrotorro‧tor /ˈrəʊtə $ ˈroʊtər/ noun [countable] technical 1 TEMa part of a machine that turns around on a central point2 
(also rotor blade)TTA the long flat part that turns around and around on top of a helicopter
(also rotor blade)TTA the long flat part that turns around and around on top of a helicopterExamples from the Corpus
rotor• The experimental results that encouraged the financiers to support a rotor ship were truly spectacular.• This may require new materials - the experimental rotor is built of wood, which Wortmann says has the best damping.• Dark mosquito shadows across the hilltops, rotor blades beating the air, stirring the ground, pressing down.• The swirling wind from my rotors whipped the fatigues of interested watchers to a blur.• The turbine whined familiarly and the rotors blurred above the cabin.• I skidded ten feet when I hit, and the rotors quietly slowed and stopped.• When I flared, the rotor wash stirred up the dust and everything vanished.• The young man was killed after becoming entangled in the unguarded rotors of a power harrow while attempting to remove a stone.Origin rotor (1800-1900) rotator “something that rotates” ((17-21 centuries)), from Latin, from rotare; → ROTATE 