rotor

American  

[roh-ter] / ˈroʊ tər /

noun

1. Electricity. a rotating member of a machine.

2. Aeronautics. a system of rotating airfoils, as the horizontal ones of a helicopter or of the compressor of a jet engine.

3. 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.

4. (in a self-winding watch) a weight eccentrically mounted on an arbor for keeping the mainspring wound.

---

rotor British  

/ ˈrəʊtə /

noun

1. 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

2. a device having blades radiating from a central hub that is rotated to produce thrust to lift and propel a helicopter

3. the revolving arm of the distributor of an internal-combustion engine

4. a violent rolling wave of air occurring in the lee of a mountain or hill, in which the air rotates about a horizontal axis

---

Etymology

Origin of rotor

First recorded in 1873; short for rotator

Example Sentences

The Black Hawk helicopter was ready for take off – its rotor blades slicing through the air in the deadening heat of the Colombian Amazon.

From BBC

“And each time you press a letter on the keyboard, at least one of the rotors moves.”

From Literature

But the holes were too small and the rotors were too loud, and a few minutes later, the helicopter thundered away without even knowing they were there.

From Literature

As the light show unfolded, the lantern's blindingly bright facades concealed a flurry of activity behind, as teams of people turned large metal barrels called rotors by hand to produce a kaleidoscopic effect.

From Barron's

On 11 January, the crew said they were woken by the sound of helicopter rotors overhead and a US Navy ship pulling alongside.

From BBC