The term 'horse-stopping cry' is a phrase used to describe the sound made by a rider to stop a horse. The most common sound used for this purpose is 'WHOA, ' which is a four-letter word. This sound is used to signal the horse to stop, slow down, or turn. It is also used to indicate that the horse should stand still and wait for further instructions. Horse-stopping cries are an important part of horsemanship and can be used to help keep the horse and rider safe.