The gait of a horse refers to the different sequences in which the horse's feet touch the ground
Western horse jogs and lopes
English horse trots and canters
The walk has four beat rhythm. Each foot is picked up and set down in sequence. The horse's back is level at the walk
Trot/Jog has a two beat rhythm. Diagonal front and hind feet move at the same time. This is called diagonal movement. The horse's back has a regular up and down movement.
Canter/lope is a three beat gait with a movement of suspension (hesitation). The head and neck are carried above the natural position of the neck to lift the forequarters and help front leg action.
Gallop is a horse's fastest gait, and is a four beat gait, with a movement of suspension. The body of a horse is more stretched out when it gallops than with any other gait
Backup is a two beat rhythm at diagonal pairs
Stride is the term used to measure the distance covered between two successive steps of the same hoof in any gait.
When the horse lopes/canters, it reaches further front with one leg that is called the lead
When the front and hind legs are not on the same lead, it is called crossfiring