In metrology, error (or measurement error) is an estimate of the difference between the measured value and the probable true value of the object of the measurement.
A calibration standard is an IM&TE item, artifact, standard reference material, or measurement transfer standard that is designated as being used only to perform calibrations of other IM&TE items.
A calibration seal is a device, placard, or label that, when removed or tampered with, and by virtue of its design and material, clearly indicates tampering.
A calibration program is a process of the quality management system that includes management of the use and control of calibrated inspection, and test and measuring equipment (IM&TE), and the process of calibrating IM&TE used to determine conformance to requirements or used in supporting activities.
A calibration procedure is a controlled document that provides a validated method for evaluating and verifying the essential performance characteristics, specifications, or tolerances for a model of measuring or testing equipment.