metric system 
noun
The decimal measuring system based on the metre, litre, and gram as units of length, capacity, and weight or mass. The system was first proposed by the French astronomer and mathematician Gabriel Mouton (1618–94) in 1670 and was standardized in Republican France in the 1790s.In the metric system, the base unit of weight is the gram; in the avoirdupois system, it's the pound....
- Elaborated between 1790 and 1799, the decimal metric system of weights and measures was zealously promoted under Napoleon.
- In the 1790s the French officially adopted a metric system based on the length of a quadrant of the Earth's meridian.