A bridle is the headgear which is used to control a horse when riding it. It consists of the reins and the bit. The reins are long ropelike strips held by the rider. Pulling on the reins can be used to steer or stop the horse. The bit is a piece of metal which is placed in the horse's mouth. The sides of a horse's mouth are quite sensitive, so it will pull the horse's head from side to side when the bit is pulled, which is how the horse is controlled.
