S.I. units. A system of units of measurement based on the metric system, adopted and described by the Eleventh General Conference on Weights and Measures. It involves seven base units:\\
(1) meter for length;\\
(2) kilogram for mass;\\ 
(3) second for time;\\
(4) Kelvin for temperature;\\
(5) ampere for electric current;\\
(6) candela for luminous intensity; and\\
(7) mole for amount of substance.