International decimal system of weights and measures, based on the metre (m) for length and the kilogram (kg) for mass, originally adopted in France in 1795.
All other metric units were derived from the metre, including the gram (g) for weight (1 cc of water at its maximum density) and the litre (l, or L) for capacity (0.001 cu m). In the 20th century, the metric system became the basis for the International System of Units , which is now used officially almost worldwide.