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[roh-ter] /ˈroʊ tər/
Electricity. a rotating member of a machine.
Compare stator (def 1).
Aeronautics. a system of rotating airfoils, as the horizontal ones of a helicopter or of the compressor of a jet engine.
any of a number of tall, cylindrical devices mounted on a special ship (rotor ship) and rotated in such a way that the Magnus effect of wind impinging on the cylinders is used to drive and maneuver the vessel.
(in a self-winding watch) a weight eccentrically mounted on an arbor for keeping the mainspring wound.
Origin of rotor
First recorded in 1873; short for rotator Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for rotor
Contemporary Examples
Historical Examples
  • These dummy pistons are shown at the near end of the rotor in Fig. 35.

    Steam Turbines Hubert E. Collins
  • In this A is the cylinder or casing, B the spindle or rotor, and C the blades.

    Steam Turbines Hubert E. Collins
  • The rotor of a variometer or variocoupler is a rotating coil.

    The Radio Amateur's Hand Book A. Frederick Collins
  • There are rings of blades round the rotor, tightly fixed to its surface.

  • Then you ask Tom to send a plane back to drop off my cap and rotor.

    The Scarlet Lake Mystery Harold Leland Goodwin
  • The field system is called the stator, and the armature the rotor.

  • Tesla further explained that the 110-horsepower turbine represented a single stage engine, or one composed simply of one rotor.

  • The shaft of a little one twelfth horsepower motor adjoining was connected with the rotor through the centre of the casing.

  • At each end is a bearing or support in which the rotor or moving part is held and in which it can turn freely.

British Dictionary definitions for rotor


the rotating member of a machine or device, esp the armature of a motor or generator or the rotating assembly of a turbine Compare stator
a device having blades radiating from a central hub that is rotated to produce thrust to lift and propel a helicopter
the revolving arm of the distributor of an internal-combustion engine
a violent rolling wave of air occurring in the lee of a mountain or hill, in which the air rotates about a horizontal axis
Word Origin
C20: shortened form of rotator
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for rotor

1873, irregular shortening of rotator (see rotate (v.)), originally in mathematics. Mechanical sense is attested from 1903; specifically of helicopters from 1930.

Online Etymology Dictionary, © 2010 Douglas Harper
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