Continuous stall or pen walking. Often an unhappy horse's reaction to confinement.

walking with slow regular strides

when the horse moves its legs in lateral pairs at the trot; i.e. off fore, off hind together, followed by nearside pair

A type of gait. When pacing, a horse moves both legs on the same side, forward at the same time. As they go forward, the other legs on the other side go backward.

Pacing is a 'laterial' gait in which the horse moves the legs on the same side back and forward together. Most pacers wear 'hopples' - straps connecting the legs on the same side. Pacing, or 'ambling', is a natural gait for some breeds of horse (as well as giraffes and camels) and is faster than trotting by roughly 3 seconds per mile. Pacers are also less likely to 'break', so they are more popular with punters than trotters, where the two gaits exist. As a result pacing dominates harness racing in the English-speaking world.

10% Faster run/walk

Aimless wandering or walking back and forth, often triggered by things like pain, hunger, or boredom, or by some distraction in the environment, such as noise, smell, or temperature.

Aimless wandering, often triggered by an internal stimulus (e.g., pain, hunger, or boredom) or some distraction in the environment (e.g., noise, smell, temperature).