Glossary

Originally referred to a group of units that were all derived from the meter. The units were for commercially important physical dimensions of length, area, volume, and mass (unit defined by mass of a specified volume of water). In modern metrology, a system of units is no longer traceable to a single unit, but all units of the system are traceable to a certain small number of basic units. In this sense, today’s International System of Units was developed from the metric system of units. It is the modern form of the MKSA metric system which has been expanded to seven basic units.