DOCK, in the manège, is used for a large case of leather, as long as the dock of a horse's tail, which serves it for a cover. The French call the dock troussequeue. It is made fast by straps to the crupper, and has leathern thongs that pass between his thighs, and along his flanks to the saddle-straps, in order to keep the tail tight, and to hinder it from whisking about.