A SI unit, short for Système International d'Unités (International System of Units), is the standard system of measurement used worldwide for scientific and technical purposes. It is a metric system based on seven base units:

• Meter (m): unit of length.
• Kilogram (kg): unit of mass.
• Second (s): unit of time.
• Ampere (A): unit of electric current.
• Kelvin (K): unit of thermodynamic temperature.
• Mole (mol): unit of amount of substance.
• Candela (cd): unit of luminous intensity.

Derived units are created by combining these base units through multiplication or division. The SI system is governed by the International Bureau of Weights and Measures (BIPM). Learn More at BIPM