Octal

[ok-tl] /ˈɒk tl/

adjective
1.
Also, octonary. of or relating to the number system with base 8, employing the numerals 0 through 7.
2.
relating to or encoded in an octal system, especially for use by a digital computer.
3.
(of an electronic device) having eight pins in its base for electrical connections.
noun
4.
(def 6).
octal
(ŏk’təl)
Relating to a number system having a base of 8. Each place in an octal number represents a power of 8. Octal notation has often been used in computer programming because three-digit binary numbers are readily converted into one-digit octal numbers from 0 to 7.

mathematics
Base 8. A number representation using the digits 0-7 only, with the right-most digit counting ones, the next counting multiples of 8, then 8^2 = 64, etc. For example, octal 177 is digital 127:
digit weight value 1 8^2 = 64 1* 64 = 64 7 8^1 = 8 7* 8 = 56 7 8^0 = 1 7* 1 = 7 — 127
Octal system used to be widespread back when many computers used 6-bit bytes, as a 6-bit byte can be conveniently written as a two-digit octal number. Since nowadays a byte is almost always 8-bit long the octal system lost most of its appeal to the hexadecimal system.
For a brief discussion on the word `octal’ see hexadecimal.
(1997-06-16)