brake block noun3 •One of two small blocks fitted to a brake caliper, which rub on the wheel rim when the brake is applied. •A block fitted to locomotives or rolling stock, which rubs on the steel tyre of the wheel when the brake is applied.There are two brake blocks per wheel of the locomotive, and each brake block is actuated by its own cylinder, which obviates rigging (except to the hand parking brake). — 1959 •A block (perhaps wooden) used for braking a horse-drawn vehicle. formsbrake blocks
