(1) systematic evaluation over time of some quantity
(2) by extension, evaluation over time of the performance of a system, of the occurrence of an event etc.
(1) NIST [RD15]
(2) MACC [RD13]
RD15: Prokhorov, A. V., R. U. Datla, V. P. Zakharenkov, V. Privalsky, T. W. Humpherys, and V. I. Sapritsky, Spaceborne Optoelectronic Sensors and their Radiometric Calibration. Terms and Definitions. Part 1. Calibration Techniques, Ed. by A. C. Parr and L. K. Issaev, NIST Technical Note NISTIR 7203, March 2005