The term 'IT HOLDS YOUR HORSES' can be solved by the word 'REIN', which is a four-letter word. A REIN is a type of strap or rope that is used to control a horse while riding. It is attached to the bridle and is held by the rider in order to control the horse's movements. Reins are also used to help the rider communicate with the horse, as different types of pressure on the reins can indicate different commands.