a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands.
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as smartphones, tablets and portable media players or gaming devices, household appliances and office equipment.
Questions having the gui tag refers to the User Experience and design of GUI.
Reference: http://en.wikipedia.org/wiki/Graphical_user_interface