Dictionary · Standards & Units
Conservation of a measurement standard
The set of operations necessary to preserve the metrological properties of a standard within stated limits — storage, handling, surveillance, and use discipline.
Related terms
More from Standards & Units
Conversion factor between units
The ratio of two units for quantities of the same kind — 25.4 mm/in; the numerical value changes, the quantity does not.
VIM (JCGM 200:2012) 1.24
Kind of quantity
The aspect common to mutually comparable quantities — length, mass, and energy are kinds; diameter and wavelength are both quantities of the kind length.
VIM (JCGM 200:2012) 1.2
Measurement standard (etalon)
The realization of the definition of a given quantity, with stated value and uncertainty, used as a reference — an artifact, instrument, reference material, or measuring system.
VIM (JCGM 200:2012) 5.1
Commutability of a reference material
The property demonstrated by the closeness of agreement between the relation among results for a stated quantity in the RM and the relation among results for representative routine samples, across specified procedures — whether the RM behaves like the real thing.
VIM (JCGM 200:2012) 5.15
Numerical value equation
A relation between numerical values that holds only for stated units — the form most spreadsheet formulas quietly are, and the reason unit discipline matters.
VIM (JCGM 200:2012) 1.25
Base quantity
A quantity in a conventionally chosen subset of a system of quantities in which no member can be expressed in terms of the others.
VIM (JCGM 200:2012) 1.4