A fundamental unit is a unit of measurement that is not dependent on any other unit, and all other units are derived from them. In the International System of Units (SI), there are seven fundamental units:

• Kilogram (kg) - Mass
• Meter (m) - Distance
• Second (s) - Time
• Ampere (A) - Electric current
• Kelvin (K) - Temperature
• Mole (mol) - Amount of substance or particles in matter
• Candela (cd) - Light intensity

These fundamental units are used to measure the corresponding physical quantities, and all other units of measurement are derived from them. For example, the unit of force, the Newton (N), is derived from the fundamental units of mass, distance, and time.