Hillger, Donald W. Regional and Mesoscale Meteorology Branch; National Environmental Satellite, Data, and Information Service; National Oceanic and Atmospheric Administration, Fort Collins, Colorado.
Parker, Thomas E. Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado.
Wildhack, William A. Formerly, Institute for Basic Standards, National Bureau of Standards.
Last reviewed:January 2020
- Length (meter)
- Mass (kilogram)
- Time (second)
- Electric current (ampere)
- Thermodynamic temperature (kelvin)
- Amount of substance (mole)
- Luminous intensity (candela)
- Other units and measurements
- Uncertainty in Practical Measurements
- Comparison of standards
- Sources of error
- Error analysis and reduction
- Measurement Techniques
- Related Primary Literature
- Additional Reading
The determination of the size of a physical quantity by comparison with a standard. All physical measurement is ultimately based on measurement unit standards defined by the SI-metric system. Metric units are the foundation from which all other measurement units are derived, even the conventional nonmetric units used by the United States. See also: Metric system; Units of measurement
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