Physical Quantities
Those entities which can be measured or derived from mathematical formulas are termed Physical quantities. These physical quantities are subdivided into two subcategories, fundamental and derived quantities.
Definition :
Fundamental quantities: are those quantities that can be expressed by a single type of entity and need no other entity to derive them. For example: mass, length, time...
Derived quantities: are those quantities that can be expressed in terms of fundamental quantities. For example, speed is a derived quantity that depends on length and time.