octal

octal notation or octal (ˈɒktəl)
—n
	a number system having a base 8: often used in computing, one octal digit being equivalent to a group of three bits
octal or octal
—n

octal   (ŏk'təl)  Pronunciation Key  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.

octal definition

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)