—n. 1. a pole or bar hinged to the rear axle of a cart or the like in such a way that it can brace the vehicle against a road to prevent it from rolling downhill.
2. Mining.a short timber for propping up loose walls or spacing two sets.
—v.t. to prop, support, or immobilize (a vehicle) by means of a sprag.
—v.i. to slow a vehicle by means of a sprag or, sometimes, by bracing the feet against the ground.