A physical property that can be quantified using a number and a reference unit. In metrology, a quantity is the specific attribute being measured, such as length, mass, voltage, or temperature. The true value of a quantity is what metrologists attempt to estimate when they state a measurement result and its uncertainty.
Heard on the job
The influence quantity of ambient temperature is causing our length measurements to drift.
Related terms
Measurand
The exact quantity a measurement is aimed at, pinned down tightly enough that everyone measures the same thing.
True value
The idealized exact value of a measurand, which no real measurement can reveal with certainty.
Influence quantity
A condition that is not the thing being measured but still changes the reading, such as temperature or humidity.