Metric system

The metric system is a system of units for measurement developed in late 18th century France to replace the disparate systems of measures then in use with a unified, natural and universal system. In the early metric system there were several fundamental or base units, the grad or grade for angles, the meter for length, the gram for weight and the liter for capacity. These were derived from each other via the properties of natural objects. Other units were derived from these fundamental units.

Multiples and submultiples of metric units are related by powers of ten; the names for these are formed with prefixes. This relationship is compatible with the decimal system of numbers and it contributes greatly to the convenience of metric units.

As the result of scientific progress, refinements, and different choices of base units, there have been a number of attempts at creating metric systems. The modern metric system (modern meaning post-1960) is now widely used throughout the world and is called the International System of Units (SI).