Knowledge
Metrology Dictionary
The complete VIM vocabulary — all numbered concepts of JCGM 200:2012 as faithful paraphrases with clause citations — plus clearly labeled practice terms from the GUM, ILAC, ISO and NIST guidance.
National measurement standard
A standard recognized by national authority to serve, in a state or economy, as the basis for assigning values to other standards of the same kind.
VIM (JCGM 200:2012) 5.3 · Standards & Units
Nominal indication interval
The set of values, bounded by rounded or approximate extreme indications, obtainable with a particular setting of the controls and used to designate that setting — the "0–100 V range" on a meter switch.
VIM (JCGM 200:2012) 4.4 · Instruments
Nominal property
A property of a phenomenon, body, or substance that has no magnitude — the sex of a specimen, the color sequence of a resistor, an ISO country code. It can be examined and classified, but not measured.
VIM (JCGM 200:2012) 1.30 · General
Nominal quantity value
A rounded or approximate value of a characterizing quantity of a measuring instrument that guides its appropriate use — the "100 Ω" stamped on a resistor, the "1 kg" of a weight.
VIM (JCGM 200:2012) 4.6 · Instruments
Normalized error (En)
The interlaboratory comparison statistic En = (x − X) / √(U²(x) + U²(X)). |En| ≤ 1 indicates agreement within expanded uncertainties; it is the standard scoring for calibration proficiency tests.
ISO 13528:2022 · Statistics
Null measurement uncertainty
The measurement uncertainty when the specified measured value is zero — what limits how confidently a null or tare reading can be trusted.
VIM (JCGM 200:2012) 4.29 · Instruments
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 · Standards & Units
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 · Standards & Units