Bis forBridle
A bridle is a piece of equipment that a horse wears on its face. A bridle is usually made from leather, and is held on by buckles. The metal part of the bridle that goes in the horses's mouth is called the bit, and the long straps connected to the bit are called reins.
The combination of bridle, bit and reins is used to direct the horse, so you can make it go in the direction you want it to when you are riding or driving it.