The Free On-line Dictionary of Computing (30 December 2018):

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 system.  The success of the Macintosh user
   interface was partly due to its consistency.

   Because of the perceived importance of look and feel, there
   have been several legal actions claiming breech of copyright
   on the look and feel of user interfaces, most notably by
   Apple Computer against Microsoft and Hewlett-Packard (which
Apple
   lost) and, later, by Xerox against Apple Computer.  Such legal
   action attempts to force suppliers to make their interfaces
   inconsistent with those of other vendors' products.  This can
   only be bad for users and the industry as a whole.

   (1995-03-03)