pinion

Many cars use rack-and-pinion steering, in which the steering wheel turns a small-toothed pinion gear, which engages the larger rack that turns the car's wheels.

Pinions make steering easy and smooth. This is true for cars as well for birds — pinion can also refer to a bird's wing or a large wing feather. Pinion comes to English through Old French, but the word ultimately derives from Latin pinna, meant both "feather" and "battlement."

Definitions of pinion
  1. noun
    wing of a bird
    synonyms: pennon
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    type of:
    wing
    a movable organ for flying (one of a pair)
  2. noun
    any of the larger wing or tail feathers of a bird
    synonyms: flight feather, quill, quill feather
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    types:
    primary, primary feather, primary quill
    one of the main flight feathers projecting along the outer edge of a bird's wing
    tail feather
    feather growing from the tail (uropygium) of a bird
    sickle feather
    one of the long curved tail feathers of a rooster
    type of:
    feather, plumage, plume
    the light horny waterproof structure forming the external covering of birds
  3. verb
    cut the wings off (of birds)
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    type of:
    disable, disenable, incapacitate
    make unable to perform a certain action
  4. verb
    bind the arms of
    synonyms: shackle
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    type of:
    confine, hold, restrain
    to close within bounds, limit or hold back from movement
  5. noun
    a gear with a small number of teeth designed to mesh with a larger wheel or rack
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    types:
    lantern pinion, lantern wheel
    a small pinion having cylindrical bars instead of teeth, used chiefly in inexpensive clocks
    type of:
    cogwheel, gear, gear wheel, geared wheel
    a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion
Word Family