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.
Definitional uncertainty
The component of uncertainty resulting from the finite detail in the definition of the measurand itself — the floor below which no better procedure can go without redefining the quantity.
VIM (JCGM 200:2012) 2.27 · Uncertainty