There is a long-list of terminology related to horse racing, too long to put here. Though two of the main terms you’ll hear are “length” and “hand”. A hand measures equal to four inches and is used to measure the height of a horse. The measurement begins at the ground and spans to as high as the shoulder of the animal. The Length is simply used as a general unit of measurement, which is approximately equal to 8 feet. It’s not a measurement used for one individual horse or a standardized size for racehorses, but a measure used to describe the length between horses. So you’ll often hear commentators discussing the distance between two runners using this term.