Final answer:
An independent, fundamental quantity of measurement in the metric system is known as a 'fundamental unit'. Fundamental physical quantities like length and mass are measured in these units, and all other quantities are derived from them.
Step-by-step explanation:
The two-word term for an independent, fundamental quantity of measurement in the metric system from which all other quantities can be derived is fundamental units. In physics, the fundamental physical quantities are length, mass, time, and electric current, which are measured in fundamental units such as the meter, kilogram, second, and ampere. All other physical quantities, including volume, force, and energy, are described as derived units, which are mathematical combinations of these fundamental units.