X Window System

The X Window System, often called "X11," is a software framework that manages the graphical interface on many Unix and Linux computers. It acts as a bridge between the computer’s hardware and applications, enabling users to open windows, move their contents, and interact visually. X11 handles the rendering of graphics and user input, often allowing the display to be on one machine while applications run on remote servers. This flexibility makes it a foundational technology for graphical user interfaces in many operating systems, enabling efficient, networked, and multi-user graphical interactions.