rotor

 
Pronunciation: /ˈrəʊtə/

noun

  • 1a rotary part of a machine, in particular:
  • a hub with a number of radiating aerofoils that is rotated in an approximately horizontal plane to provide the lift for a rotary wing aircraft.
  • the rotating assembly in a turbine.
  • the armature of an electric motor.
  • (also rotor arm) the rotating part of the distributor of an internal-combustion engine which successively makes and breaks electrical contacts so that each spark plug fires in turn.
  • the rotating container in a centrifuge.
  • 2 Meteorology a large eddy in which the air circulates about a horizontal axis, especially in the lee of a mountain: [as modifier]: a rotor cloud

Origin:

early 20th century: formed irregularly from rotator