Definition:Fundamental Unit (Physics)

Definition

A fundamental unit is a unit of measurement for a measurable physical property from which every other unit for that quantity can be derived.

The fundamental unit for a particular measurable quantity is chosen by convention.

They are the units of the fundamental dimensions of physics.

Also known as

Fundamental units are also known as base units.

Examples

There are various conventions, as follows:

• SI units (Système International), which evolved from the MKS system
• MKS, that is, Metre-Kilogram-Second
• CGS, that is, Centimetre-Gram-Second
• Imperial or FPS: that is, Foot-Pound-Second.
• Metric System: a more-or-less colloquial name for the system of measurement of values derived from length based on the metre.

There are other more specialized ones.

Also see

• Definition:Derived Unit

• Results about fundamental units in the context of physics can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): base units
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): base units