International System of Units (SI)
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Definition
The modern metric system of measurement, accepted worldwide for scientific and commercial use.
Explanation
SI defines seven base units: meter, kilogram, second, ampere, kelvin, mole, and candela. All other units are derived from these.
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RELATED TERMS
Meter
The SI base unit of length, defined as the distance light travels in 1/299,792,458 of a second.
Kilogram
The SI base unit of mass, defined by the Planck constant.
Second
The SI base unit of time, defined by the cesium-133 atom.
Kelvin
The SI base unit of temperature, starting at absolute zero.
Ampere
The SI base unit of electric current.