A natural three-beat gait of a horse, faster than a canter, in which all four feet are off the ground at the same time during each stride. A fast running motion of other quadrupeds. A ride taken at a gallop. A rapid pace: Events were proceeding at a gallop. Medicine A disordered rhythm of the heart characterized by three or four distinct heart sounds in each cycle and resembling the sound of a galloping horse. Also called cantering rhythm, gallop rhythm. To cause to gallop. To transport at or as if at a gallop: gallop the mail to the next station. To ride a horse at a gallop. To move or progress swiftly: Summer was galloping by.