A numbering system that uses eight digits. It is used as a shorthand method for representing binary characters that use six-bits. Each three bits (half a character) is converted into a single octal digit. Okta is Greek for 8.

      Decimal  Binary   Octal
      0        000      0
      1        001      1
      2        010      2
      3        011      3
      4        100      4
      5        101      5
      6        110      6
      7        111      7