GUI stands for graphical user interface. The most popular graphical user interfaces use windows, icons and menus to open applications, organize files and manage files.
Graphical user interfaces allow computer users to manage their devices without needing to enter complicated codes and commands. The graphical user interface is one of the biggest reasons why computers started to dominate the workplace in the 1980s and continue to do so today. The most popular graphical user interfaces, as of 2014, are Microsoft Windows and Apple OS X. Because of the increasing popularity of mobile devices, Google's Android interface and Apple's iOS now control a good share of the market.