The unit of measurement used in the metric system is the kilogram. The metric system is an internationally recognized system of measurement that is based on multiples of 10. The kilogram is used to measure mass or weight.
In the metric system, prefixes are added to the base unit to represent different quantities. For example, a milligram is one thousandth of a gram, and a kilogram is equal to 1000 grams.
Other units of measurement in the metric system include meters for length, liters for volume, and seconds for time. These units can also have prefixes added to them to represent different quantities.
To summarize, in the metric system, the unit of measurement for mass or weight is the kilogram.