Definition:Octal Notation

Definition
Octal is another word for base $8$.

That is, every number $x \in \R$ is expressed in the form:
 * $\displaystyle x = \sum_{j \mathop \in \Z} r_j 8^j$

where:
 * $\forall j \in \Z: r_j \in \left\{{0, 1, \ldots, 7}\right\}$

It used to be important in the field of computer science, but is less so nowadays, as hexadecimal has proved itself more convenient in general.

Also known as
Octal numbers are also known as octonary or octenary.