This is a trick question, but a lot of people do think they are different things. The difference between the canter and the lope is the saddle strapped to the horse's back. The word "lope" is used by western riders and rodeo people, but the rest of the English speaking world uses "canter."
In the same vein, western people call the "trot" the "jog." (Jog also means to lightly work a racehorse).
Although there's some difference in the way of going between English and Western horses, the gaits are basically the same.
So. No difference at all.