metric system

In the most general sense, a metric system is any system used to measure things. Usually, however, the term refers to systems of units that include the meter or centimeter as the unit of length, the kilogram as the unit of mass and the second as the unit of time, and that employ only decimal multiples and subdivisions of those units, which are identified by attaching prefixes to the names of the units. The current version of the metric system, used in both science and trade since 1960, is the International System of Units.

These systems originated in France in the late 18ᵗʰ century; for historical details see meter and kilogram.

For nation-by-nation details on the spread of the metric systems, see this chart.

The centimeter-gram-second and meter-kilogram-second systems are examples of obsolete metric systems formerly used in scientific work.