Measurement uncertainty
Also: uncertainty
A quantified doubt about which values could reasonably correspond to the measurand.
Uncertainty combines stated sources and coverage assumptions; it is distinct from tolerance, error, and repeatability.
Example Report 100.2 mm ± 0.3 mm under the documented method, not simply 100.2 mm.
Common misconception Uncertainty is not a confession of bad work and does not mean every value in the interval is equally likely.