Definition of "sprag" []

• 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. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "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."
• "Du Toit: "Was it safe not to put the aeroplane sprag and the farm gate safety devices back in place before knocking off?""
• "The 'Silesian' method includes a "soldier sprag" brace wedged between the props underneath the roof bar to reinforce the props against lateral compressive forces."