sequence of measurement standards and calibrations that is used to relate a measurement result to a reference
NOTE 1 A metrological traceability chain is defined through a calibration hierarchy.
NOTE 2 A metrological traceability chain is used to establish metrological traceability of a measurement result.
NOTE 3 A comparison between two measurement standards may be viewed as a calibration if the comparison is used to check and, if necessary, correct the quantity value and measurement uncertainty attributed to one of the measurement standards.