Xbit

Xbit is a term used across several technical domains to refer to different concepts, rather than a single standardized definition. In digital design and simulation, the letter X commonly denotes an unknown or indeterminate value. An x-bit, in this sense, is a single bit that may be 0, 1, or X, reflecting uncertainty as signals propagate through a circuit or model.

In Unix-like operating systems, the execute permission is often described as the x-bit. For each user class—owner, group, and others—three permission bits exist: read, write, and execute. The presence of the x-bit allows a file to be executed as a program, while its absence prevents execution. The x-bit works together with the r and w bits and is modified by file permission commands such as chmod.

Beyond these areas, xbit may appear as a project-specific term, a flag in a protocol header, or a shorthand variable name in code. Because there is no universal standard for xbit, its precise meaning is determined by the context and accompanying documentation.

Overall, xbit is best understood as a contextual shorthand rather than a single, universal concept. When encountering the term, consult domain-specific sources to determine the intended meaning in that setting.