Comparison of the imperial and US customary measurement systems metre, as 1852 metres. Traditionally, both Britain and the US used three different weight systems: troy weight for precious metals, avoirdupois weight for most other purposes and apothecaries' weight for medicines. However, apothecaries' weight has now been superseded by the metric system. One important difference is the widespread use in Britain of the stone of 14 pounds () for body weight. This unit is not used in the United States, although its influence was seen in the practice, until World War II, of selling flour by a barrel of 196 pounds (14 stone). Another difference arose when Britain abolished the
Weight for Age Weight for Age Weight for Age (WFA) is a term in Thoroughbred horse racing which is one of the conditions for a race. It means that a horse will carry a set weight in accordance with the Weight for Age Scale. This weight varies depending on the horse’s age, its sex, the race distance and the month of the year. Weight for age races are usually Group 1 races, races of the highest quality. It is a form of handicapping for horse racing, but within the horse racing industry is not referred to as handicap which is reserved for more