Vector space in which the vectors of the basis have the same length.

### Example

In this case, the vector space may also be orthogonal; if so, it is said to be orthonormal, as in the following example:

\(\overrightarrow{j} \perp \overrightarrow{i}\) and \(m\left ( \overrightarrow{j} \right )=m\left ( \overrightarrow{i} \right )\)