Definition:Magnitude

Definition
The magnitude (or size) of a quantity (either vector or scalar) is a measure of how big it is.

It is usually encountered explicitly in the context of vectors:

If $\mathbf v$ is the vector quantity in question, then its magnitude is denoted:
 * $\left|{\mathbf v}\right|$

or
 * $v$

Also see

 * Vector Length
 * Absolute Value