Base-8, also known as octal, is a numeral system that uses eight distinct digits: 0, 1, 2, 3, 4, 5, 6, and 7. It is a positional system, meaning the value of a digit depends on its position in a number. For example, in the octal number 17, the '1' represents one group of eight, while the '7' represents seven units. Base-8 is often used in computing and digital systems because it can represent binary numbers more compactly. Each octal digit corresponds to three binary digits (bits), making it easier for humans to read and interpret binary data. This relationship is useful in programming and data representation, especially in systems related to Unix and file permissions.