Metric units

Metric units is an obsolete term for a system of units in which the unit of length is the meter, the unit of mass the kilogram, and the unit of time the second; this system is also referred to as the MKS system. Sometimes the unit of electric current, the ampere, is added to the system and then it is referred to as the MKSA system, a term which is also obsolete.

The metric system of units was created by French revolutionaries around 1790 (see the article on the kilogram for more details about the history) and ultimately developed into the International System of Units (Système international d'unités, hence the abbreviation SI.)