International System of Units n.
Abbr. SI
A complete, coherent system of units used for scientific work, in which the fundamental quantities are length, time, electric current, temperature, mass, luminous intensity, and amount of substance. Also called International System.
International System The English name for Système International [d'Unites], a decimal system of units used mainly in scientific work, in which the basic quantities are length, mass, time, electric current, temperature, amount of matter, and luminous intensity. In addition, the International System uses two supplementary units to measure plane angles and solid angles. See Table at measurement. |