International System of Units

Standing for Système Internationale, the official abbreviation for International System of Units. Informally used interchangeably with the term "the metric system", properly speaking the SI standard favours certain metric units such as the Joule (1 kg·m²·s⁻²) and deprecates others such as the erg (1 g⋅cm²⋅s⁻²). It is regulated and developed by three international bodies, each of them composed of representatives of member countries.