A fundamental quantity, also known as a base quantity, is a physical quantity that is independent and cannot be defined in terms of other physical quantities. Fundamental quantities are the building blocks of a system of measurement and serve as a reference for deriving other quantities. They are usually chosen based on their simplicity and importance in understanding the physical world. In the International System of Units (SI), there are seven fundamental quantities: length, mass, time, electric current, temperature, amount of substance, and luminous intensity.
