Dictionary · Standards & Units
Off-system measurement unit
A unit that does not belong to the system of units in use — the day, the electronvolt, and the nautical mile relative to the SI.
Related terms
More from Standards & Units
Numerical quantity value
The number in a quantity value — the 5.34 in 5.34 m: the ratio of the quantity to its unit.
VIM (JCGM 200:2012) 1.20
International System of Units (SI)
The system of units based on the ISQ, with unit names, symbols, prefixes, and rules for their use, adopted by the CGPM. Since the 2019 revision all seven base units are defined by fixing the numerical values of seven defining constants.
VIM (JCGM 200:2012) 1.16
Reference measurement standard
A standard designated for the calibration of other standards for quantities of a given kind in an organization or at a location — a laboratory's best standard.
VIM (JCGM 200:2012) 5.6
Conventional reference scale
A quantity-value scale defined by formal agreement — pH and the practical temperature scales are canonical examples.
VIM (JCGM 200:2012) 1.29
Reference quantity value
A quantity value used as a basis for comparison with values of quantities of the same kind — a true value, a conventional value, or a standard's certified value, depending on context.
VIM (JCGM 200:2012) 5.18
Multiple of a unit
A unit obtained by multiplying a given unit by an integer greater than one — the kilometre from the metre.
VIM (JCGM 200:2012) 1.17