Before approximately the 14th century there were two hundredweights in England, one of 100 pounds, and one of 108 pounds. In 1340, King Edward III changed the value of the stone from 12 pounds to 14 pounds. Since a hundredweight is 8 stones, the 100-pound hundredweight became 112 pounds.
The kilogram is the base unit of mass in the International (SI) System of Units, and is accepted on a day-to-day basis as a unit of weight (the gravitational force acting on any given object).
The kilogram is almost exactly equal to the mass of one litre of water.