In computing, Motif refers to both a graphical user interface (GUI) specification and the widget toolkit for building applications that follow that specification under the X Window System on Unix and other POSIX-compliant systems. It emerged in the 1980s as Unix workstations were on the rise, as a competitor to the OPEN LOOK GUI. It is now the basic building block of the Common Desktop Environment.
The Motif look and feel is distinguished by its use of square, chiseled, three-dimensional effects for its various user interface elements — menus, buttons, sliders, text boxes, and the like. Motif's operation was designed to correspond closely with the then-familiar Microsoft Windows 3.11 and OS/2's Presentation Manager interfaces, and Microsoft played a key role in designing the original style guide.
There are a few implementations of the Motif API. Motif the toolkit is the first. There is also Open Motif which is a release of the "original" Motif under more liberal licensing terms. Finally, the LessTif project aims to implement the API under the LGPL license.