An animal gallops when it runs with its legs moving quickly and in a special way. The word "gallop" can also describe other fast movements of things like trains or cars.
When people talk about something that's happening quickly, they might say that it's going at a gallop. This is often used to describe how work is flowing easily or how a plan is moving forward without any problems. For example, if you've been studying for an exam and suddenly you feel confident that you know the material, people might say that your knowledge is coming along at a gallop.
(of a horse, etc) To run at a gallop.
Example: The horse galloped past the finishing line.
Movement at a gallop.
