The Free On-line Dictionary of Computing (30 December 2018):

Système International d'Unités
Systeme International
System International
Système International

    (SI - International System of Units) The
   standard set of units of measurement set by the 11th General
   Conference on Weights and Measures in 1960.  There are seven
   base units: the metre (length), the kilogram (mass), the
   second (time), the ampere (electrical current), the kelvin
   (temperature), the mole (number of atoms) and the candela
   (luminous intensity).  These are defined either in terms of
   physical properties such as the speed of light or, in the case
   of mass, by a "prototype" lump of platinum-iridium kept at
   BIPM.  Derived units like meters per second (speed) are
   formed by combining base units.  SI also specifies a list of
   prefixes (multipliers like "k" for 1000).

   SI Home (http://www.bipm.org/en/si/).

   (2014-07-08)