Look and Feel

The appearance and function of a program's user interface.  The term is most often applied to graphical user interfaces (GUI) but might also be used by extension for a textual command language used to control a program. 

Look and feel includes such things as the icons used to represent certain functions such as opening and closing files, directories and application programs and changing the size and position of windows; conventions for the meaning of different buttons on a mouse and keys on the keyboard; and the appearance and operation of menus.

A user interface with a consistent look and feel is considered by many to be an important factor in the ease of use of a computer.