Dictionary · 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.
Related terms
More from 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.
VIM (JCGM 200:2012) 5.11
Quantity value
A number together with a reference (such as a measurement unit) expressing the magnitude of a quantity — 5.34 m, 0.152 kg, or a value on an agreed scale.
VIM (JCGM 200:2012) 1.19
Quantity calculus
The set of mathematical rules applied to quantities rather than bare numbers — the algebra by which units propagate through equations.
VIM (JCGM 200:2012) 1.21
Reference data
Data related to a property of a phenomenon, body, or substance — or to a system of components of known composition or structure — obtained from an identified source, critically evaluated, and verified for accuracy.
VIM (JCGM 200:2012) 5.16
Quantity
A property of a phenomenon, body, or substance to which a magnitude can be assigned and expressed as a number and a reference (typically a measurement unit).
VIM (JCGM 200:2012) 1.1
System of units
A set of base and derived units, with their multiples and submultiples, defined under given rules for a given system of quantities.
VIM (JCGM 200:2012) 1.13