One application is as a measurement device for dimensional metrology. Multimeters used for critical measurements may be part of a metrology program to assure calibration. The science of measurement is pursued in the field of metrology. Probing systems for microscale metrology applications are another emerging area. Scale of temperature is a methodology of calibrating the physical quantity temperature in metrology. Humidity measurement is among the more difficult problems in basic metrology. Not all calibration is an affair for metrology labs. Capacitive displacement sensors are often used in metrology applications. In particular, an improvement in wafer metrology is required. Electrical measurements are a branch of the science of metrology. There are strong links between quantum metrology and quantum information science. Moreover, the Paris meridian was linked with international collaboration in geodesy and metrology. The focus is on the metrology of 3-dimensional Nano systems. The calculation is exemplified for silicon, whose relative atomic mass is especially important in metrology. Industrial CT scanning allows for full non-destructive metrology.