Metrology (from Greek μετρoν measured and λoγoς, treaty) is the science of measurement and its applications, which includes all theoretical and practical aspects of measurement, whatever their measurement uncertainty and its scope (VIM 2008 ), for example: mass, length, time, volume, temperature, etc.., so it is easy to understand that the metrology is present in all domains of science.

Metrology as its scope is divided into:

• Scientific Metrology
• Industrial Metrology
• Legal Metrology

It deals with the study, organization, maintenance and development of standards supported by scientific theories and work in the recognition and equivalence of these internationally. In general, the scientific metrology is developed by the called National Metrology Institutes (NMI).

Aimed at ensuring the measurements being made in the various branches of industry. The industry is forced to make measurements on raw materials, processes and finished products, dealing among other applications, the finished products conform to quality standards and specifications or keep within the parameters established manufacturing processes. The quality of a product may not be better than the quality of measurements to manufacture, they are inextricably linked.

Legal metrology comprises all activities for which legal requirements are prescribed on measurement, units of measurement, measuring instruments and methods of measurement. These activities being performed by or on behalf of governmental authorities, in order to ensure an appropriate level of credibility of measurement results in such socially important fields such as trade, health, environmental protection.