from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A piece of wood or metal wedged beneath a wheel or between spokes to keep a vehicle from rolling.
  • noun A pointed stake lowered at an angle into the ground from a vehicle to prevent movement.
  • noun A prop to support a mine roof.

from The Century Dictionary.

  • noun A bar of steel attached by one end to a wagon or motor-car frame or body, while the other end (which is sharpened) can be let down at an angle with the ground, to prevent the vehicle from running backward down hills or grades.
  • To prop by a sprag; also, to stop, as a carriage on a steep grade, by putting a sprag in the spokes of the wheel.
  • noun A young salmon of the first year; a smolt.
  • noun A half-grown cod.
  • A dialectal form of sprack.
  • noun A billet of wood.
  • noun Specifically In coal-mining: A short billet of wood used instead of a brake to lock the wheels of a car.
  • noun A short wooden prop used to support the coal during the operation of holing or undercutting; a punch-prop.

from the GNU version of the Collaborative International Dictionary of English.

  • transitive verb To check the motion of, as a carriage on a steep grade, by putting a sprag between the spokes of the wheel.
  • transitive verb To prop or sustain with a sprag.
  • noun A billet of wood; a piece of timber used as a prop.
  • noun (Zoöl.), Prov. Eng. A young salmon.
  • adjective See sprack, a.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a wooden prop used to support the roof of a mine
  • noun a chock or bar wedged under a wheel or between the spokes to prevent a vehicle from rolling down an incline


from The American Heritage® Dictionary of the English Language, 4th Edition

[Perhaps of Scandinavian origin.]


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  • A new worker's attempts to "sprag," or stop the wheels, the cars with a piece of wood was in vain and the three loaded cars plummeted down the shaft and crashed into the descending elevator, Wolensky and Hastie said.

    Times Leader News 2009

  • Du Toit: "Was it safe not to put the aeroplane sprag and the farm gate safety devices back in place before knocking off?"

    ANC Daily News Briefing 1995

  • The 'Silesian' method includes a "soldier sprag" brace wedged between the props underneath the roof bar to reinforce the props against lateral compressive forces.

    5.1 Rigid support in drifts and stopes 1993

  • But I'll put a sprag in your wheel afore you gang far.

    The Underworld The Story of Robert Sinclair, Miner James C. Welsh

  • But the epitaphs were trim, and sprag, and potent, and pleased the survivors of Thames-Ditton above the old Mumpsimus of 'Afflictions

    Highways and Byways in Surrey Eric Parker 1912

  • For all that, it's a sheer impossibility that you should guess who put a sprag in the wheel of Hilton's chariot.

    The Strange Case of Mortimer Fenley Louis Tracy 1895

  • [But the] epitaphs were trim and sprag & patent, & pleased the survivors of Thames Ditton above the old mumpsimus of

    The Works of Charles and Mary Lamb — Volume 5 The Letters of Charles and Mary Lamb Mary Lamb 1805

  • BorgWarner produces transmission components, including friction plates and sprag one-way clutch assemblies, for the optional six-speed automatic transmission.

    Automotive Headlines 2010

  • As the huge pendulum below the Clock rocks the Chronophage as he steps round the great escapewheel, each backward and forward movement is used by sprag clutches to wind up the drive spring.

    My[confined]Space 2008


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