Definition:  coherent system of units based on the International System of Quantities (ISQ), their names and symbols, including a series of prefixes and their names and symbols, together with rules for their use, adopted by the General Conference on Weights and Measures (CGPM)
Note 1 to entry: The SI is founded on the seven base quantities of the ISQ and the names and symbols of the corresponding base units that are contained in the following table:
Base quantity

Base unit

Name

Name

Symbol

length

metre

m

mass

kilogram

kg

time, duration

second

s

electric current

ampere

A

thermodynamic temperature

kelvin

K

amount of substance

mole

mol

luminous intensity

candela

cd

Note 2 to entry: The base units and the coherent derived units of the SI form a coherent set, designated the "set of coherent SI units".
Note 3 to entry: For a full description and explanation of the International System of Units, see the current edition of the SI brochure published by the International Bureau of Weights and Measures (BIPM) and available on the BIPM website.
Note 4 to entry: In quantity calculus, the quantity "number of entities" is often considered to be a base quantity, with the base unit one, symbol 1.
Note 5 to entry: The SI prefixes for multiples and submultiples of units are given in IEV 1120203.
