What is a kilogram?
A kilogram is metric unit of weight subdivided into 1,000 grams. The base unit of mass in the International System of Units (SI) is a kilogram and not, as is quite often mistaken, the gram.
One liter of water weighs 1kg.
What is an avoirdupois ounce?
An avoirdupois ounce is a unit of weight in the avoirdupois system, commonly used in the United States and other countries for measuring goods that are typically sold by weight.
It is equal to 1/16 of a pound or approximately 28.35 grams. The avoirdupois system is based on a pound of 16 ounces, with larger units such as tons and pounds used for heavier measurements.