GUI

Graphical user interface.

Well known examples of software with a GUI would be Photoshop or the GIMP, Firefox, and Inkscape. Many Linux software programs like the GIMP, Firefox, Inkscape, while primarily offering a grpahical interface, may also offer certain functionality via the command line. Try running them from the shell with the "--help" option, or view their man pages to find out more.

See Wikipedia:Graphical User Interface

Contrast with Command-line Interface.