A prompt that a rider gives a horse to change gaits, turn, etc., using the hands, legs, voice or body weight.
An aid is an action by a part of the rider or handler's body to a part of the horse's body to cause the horse to react in a particular way. An aid is almost never used alone but always used in conjunction with other aids. A rider's natural aids are his or her mind, seat, weight, upper body, legs, hands, and voice. The combined use of all of the rider's aids simultaneously produces a smooth, balanced response from a horse. A handler's natural aids are the mind, hands, and overall body language. Examples of Artificial Aids (which are extensions, reinforcements, or substitutions for the natural aids) are whips, spurs, and nosebands.