Horse length
A horse length, or simply length, is a unit of measurement for the length of a horse from nose to tail, approximately.
Use in horse racing
The length is commonly used in Thoroughbred horse racing, where it describes the distance between horses in a race. Horses may be described as winning by several lengths, as in the notable example of Secretariat, who won the 1973 Belmont Stakes by 31 lengths. In 2013, the New [York Racing Association] placed a blue-and-white checkered pole at Belmont Park to mark that winning margin; using Equibase's official measurement of a length——the pole was placed from the finish line.More often, winning distances are merely a fraction of a length, such as half a length. In British horse racing, the distances between horses are calculated by converting the time between them into lengths by a scale of lengths-per-second. The actual number of lengths-per-second varies according to the type of race and the going conditions. For example, in a flat turf race run on good going, a value of six lengths-per-second is used; in a national hunt race on heavy going, where horses are assumed to be moving more slowly, the value is four lengths-per-second.
Other measures
Distances smaller than that are similarly described in reference to the equine body with terms such as a "neck", and a "head", a "short head" or "nose", the smallest possible named advantage by which a horse can win. In Ireland a margin of more than 30 lengths is described as a "distance". In the United Kingdom, the maximum recognised distance is 99 lengths, with anything over this being referred to as "99+ lengths". In France the term "short neck" is used for a margin intermediate between a head and a neck. Harness race finishing margins are typically measured in meters.Other uses
These terms are used in other disciplines of equestrianism as well. It is particularly useful as a guide for riders in spacing animals apart when a number of them are all together in a riding arena such as during group riding instruction or at a horse show.Abbreviations
In reporting result of horse races winning margins are commonly abbreviated:| Margin | Abbreviation |
| Nose | ns |
| Head | hd |
| Neck | nk |
| Half a length | 1/2 |
| Three quarters of a length | 3/4 |