One stone is equivalent to 14 pounds. The stone is a British unit of dry measurement that is commonly used in Great Britain and Ireland.
The term "stone" got its name from the practice of using rocks or stones as weights, especially when trading. By the 14th century, because of England's wool exports, it was necessary to fix an exact weight to the term. Thus in 1389 a royal statute declared that one stone of wool equaled 14 pounds.
As of 2014, the stone is still used in Great Britain to express weight in sports, including boxing, wrestling and horse racing.