What is SI unit?

The International System of Units (SI) is the modern form of the metric system and is the most widely used system of measurement in the world. It is based on seven base units: the meter (length), kilogram (mass), second (time), ampere (electric current), kelvin (temperature), mole (amount of substance), and candela (luminous intensity). These base units can be combined to derive other units for different physical quantities.

The International System of Units, abbreviated as SI (from the French: Système international d'unités), is the modern form of the metric system and is the most widely used system of measurement. It is based on seven base units, which are the second, meter, kilogram, ampere, kelvin, mole, and candela. All other units in the SI are derived from these base units.