Dictionary · Standards & Units
Unit equation
A mathematical relation between base and derived units — N = kg·m·s⁻².
Related terms
More from Standards & Units
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
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
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
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
Quantity of dimension one
A quantity whose dimension has all base-quantity exponents equal to zero — refractive index, strain, a ratio of like quantities; often loosely called "dimensionless".
VIM (JCGM 200:2012) 1.8
Ordinal quantity
A quantity defined by an agreed procedure that can be ranked but has no meaningful algebra — Rockwell hardness or earthquake magnitude: order exists, differences and ratios do not.
VIM (JCGM 200:2012) 1.26