The term 'BRIDLE MOUTHPIECE' is a combination of two words, 'BRIDLE' and 'MOUTHPIECE'. A BRIDLE is a piece of equipment used to control a horse, usually consisting of a headstall, BIT, and reins. The MOUTHPIECE is the part of the BRIDLE that goes into the horse's mouth, typically made of metal or rubber. The BIT is the part of the BRIDLE that goes into the horse's mouth and is used to control the horse's movements. The BIT is usually made of metal and has a variety of shapes and sizes. The BRIDLE MOUTHPIECE is an important part of the BRIDLE and helps the rider control the horse.