1. A chock or bar wedged under a wheel or between the spokes to prevent a vehicle from rolling down an incline
   "They used a sprag to keep the wagon from rolling while they unloaded it"
    
2. A wooden prop used to support the roof of a mine
   "The miners installed additional sprags to reinforce the tunnel";
   - pitprop

Derived forms: sprags

Type of: chock, prop, wedge

Encyclopedia: Sprag