A measure of weight, being a thousand grams, equal to 2.2046226 pounds avoirdupois (15,432.34 grains). It is equal to the weight of a cubic decimeter of distilled water at the temperature of maximum density, or 39° Fahrenheit.
The SI unit of mass, a quantity about equal to 2.2 pounds.
Kilogram (kg) is the SI base unit of mass; it is equal to the mass of the international prototype of the kilogram. The prototype of the standard is a cylinder of platinum-iridium alloy, 39 mm in diameter and 39 mm high. Prototype of the kilogram kept by the Bureau International des Poids et Mesures (International Bureau of Weights and Measures) at S?evres, near Paris.