Definition - What does Kilogram (kg) mean?
The kilogram (kg) is an accepted SI unit of measurement for the mass of an object. When converted to English standard units it is equivalent to about 2.2 pounds. One kilogram is equal to 1,000 grams.
Universally accepted units of measurement for the weight or mass of an object are kilograms, grams and pounds.
Corrosionpedia explains Kilogram (kg)
The kilogram was first introduced as a prototype in 1799; previously only grams were considered as a universal unit when expressing the mass or weight of an object. At that time, one gram was defined as one cubic centimeter of water at the melting point of ice (0°C).