Desktop metaphor in the context of Desk accessory

In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, while the machine simultaneously feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls and process controls. The design considerations applicable when creating user interfaces are related to, or involve such disciplines as, ergonomics and psychology.

Generally, the goal of user interface design is to produce a user interface that makes it easy, efficient, and enjoyable (user-friendly) to operate a machine in the way which produces the desired result (i.e. maximum usability). This generally means that the operator needs to provide minimal input to achieve the desired output, and also that the machine minimizes undesired outputs to the user.

In computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphical shell. The desktop environment was seen mostly on personal computers until the rise of mobile computing. Desktop GUIs help the user to easily access and edit files, while they usually do not provide access to all of the features found in the underlying operating system. Instead, the traditional command-line interface (CLI) is still used when full control over the operating system is required.

A desktop environment typically consists of icons, windows, toolbars, folders, wallpapers and desktop widgets (see Elements of graphical user interfaces and WIMP). A GUI might also provide drag and drop functionality and other features that make the desktop metaphor more complete. A desktop environment aims to be an intuitive way for the user to interact with the computer using concepts which are similar to those used when interacting with the physical world, such as buttons and windows.

Future Concepts division (formerly Palo Alto Research Center, PARC and Xerox PARC) is a research and development company in Palo Alto, California. It was founded in 1969 by Jacob E. "Jack" Goldman, chief scientist of Xerox Corporation, as a division of Xerox, tasked with creating computer technology-related products and hardware systems.

Xerox PARC has been foundational to numerous revolutionary computer developments, including laser printing, Ethernet, the modern personal computer, graphical user interface (GUI) and desktop metaphor–paradigm, object-oriented programming, ubiquitous computing, electronic paper, amorphous silicon (a-Si) applications, the computer mouse, and very-large-scale integration (VLSI) for semiconductors.

In user interface design, an interface metaphor is a set of user interface visuals, actions and procedures that exploit specific knowledge that users already have of other domains. The purpose of the interface metaphor is to give the user instantaneous knowledge about how to interact with the user interface. They are designed to be similar to physical entities but also have their own properties (e.g., desktop metaphor and web portals). They can be based on an activity, an object (skeuomorph), or a combination of both and work with users' familiar knowledge to help them understand 'the unfamiliar', and placed in the terms so the user may better understand.

An example of an interface metaphor is the file and folder analogy for the file system of an operating system. Another example is the tree view representation of a file system, as in a file manager.

A wallpaper or background (also known as a desktop background, desktop picture or desktop image on computers) is a digital image (photo, drawing etc.) used as a decorative background of a graphical user interface on the screen of a computer, smartphone or other electronic device. On a computer, wallpapers are generally used on the desktop, while on a mobile phone they serve as the background for the home screen. Though most devices include a default background image, modern devices usually allow users to manually change the background image.

The term "wallpaper" was used in Microsoft Windows before Windows XP (In Windows XP and later, it is called the "desktop background"). Meanwhile, macOS refers to it as "desktop picture". On older systems that allowed small repeated patterns to be set as background images, the term desktop pattern was used.