Bridle control is a term used to describe the use of reins to control a horse. It is a form of communication between the rider and the horse, allowing the rider to direct the horse's movements. The term 'REIN' is a four-letter word that is used to refer to the leather straps that are attached to the bridle and held by the rider. Bridle control is an important part of horsemanship and is essential for safe and effective riding.