What does stone mean in terms of weight?

The stone is a British measurement of weight that is equal to 14 pounds or approximately 6.35 kilograms. Although this unit is no longer common in Great Britain for most measurements, it is still used to express human body weight.

Historically, the stone was a local weight standard that varied widely between different locations. The weight was frequently set based on a stone that had been chosen for use in weighing different goods. The stone stood for anywhere between 3 and 40 pounds, depending on the location. In Britain, a stone of different commodities stood for different weights. For example, a stone of wool was 14 pounds, but a stone of mutton was only 8 pounds.