The acronym 'GUI' stands for Graphical User Interface, which is a visual interface that allows users to interact with software through graphical elements like buttons, icons, and menus. GUIs replace text-based command-line interfaces, enabling more intuitive interaction and accessibility for users. The implementation of GUIs has significantly enhanced user experience, making software easier to use, especially for non-technical users. This accessibility has contributed to the widespread adoption of personal computers and mobile devices.