Definition of International System in US English:

International System


  • 1A system of physical units having as base units the metre, kilogram, second, ampere, kelvin, candela, and mole, with derived units defined in terms of these by a set of prefixes indicating multiplication or division by a power of ten; abbreviated SI.

  • 2Engineering. A system of dimensions and proportions for screw threads for screws and bolts of various sizes, based on metric units of measurement. Now chiefly historical.


Mid 19th century (in an earlier sense). From international + system.