🔗 Logo of the X Window System ca. 1990?

🔗 Computing 🔗 Computing/Software 🔗 Computing/Free and open-source software 🔗 Linux

The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems.

X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting with a mouse and keyboard. X does not mandate the user interface – this is handled by individual programs. As such, the visual styling of X-based environments varies greatly; different programs may present radically different interfaces.

X originated as part of Project Athena at Massachusetts Institute of Technology (MIT) in 1984. The X protocol has been at version 11 (hence "X11") since September 1987. The X.Org Foundation leads the X project, with the current reference implementation, X.Org Server, available as free and open-source software under the MIT License and similar permissive licenses.