In computing, an avatar is a graphical representation of a user, the user's character, or persona. Avatars can be two-dimensional icons in Internet forums and other online communities, where they are also known as profile pictures, userpics, or formerly picons (personal icons, or possibly "picture icons"). Alternatively, an avatar can take the form of a three-dimensional model, as used in online worlds and video games, or an imaginary character with no graphical appearance, as in text-based games or worlds such as MUDs.

The term avatāra (/ˈævətɑːr, ˌævəˈtɑːr/) originates from Sanskrit, and was adopted by early computer games and science fiction novelists. Richard Garriott extended the term to an on-screen user representation in 1985, and the term gained wider adoption in Internet forums and MUDs. Nowadays, avatars are used in a variety of online settings including social media, virtual assistants, instant messaging platforms, and digital worlds such as World of Warcraft and Second Life. They can take the form of an image of one's real-life self, as often seen on platforms like Facebook and LinkedIn, or a virtual character that diverges from the real world. Often, these are customised to show support for different causes, or to create a unique online representation.

Academic research has focused on how avatars can influence the outcomes of communication and digital identity. Users can employ avatars with fictional characteristics to gain social acceptance or ease social interaction. However, studies have found that the majority of users choose avatars that resemble their real-world selves.

The word avatar is ultimately derived from the Sanskrit word (avatāra /ˈævətɑːr, ˌævəˈtɑːr/); in Hinduism, it stands for the "descent" of a deity into a terrestrial form. It was first used in a computer game by the 1979 PLATO role-playing game Avatar. In Norman Spinrad's novel Songs from the Stars (1980), the term avatar is used in a description of a computer generated virtual experience. In the story, humans receive messages from an alien galactic network that wishes to share knowledge and experience with other advanced civilizations through "songs". The humans build a "galactic receiver" that allows its users to engage in "artificial realities". One experience is described as such:

You stand in a throng of multifleshed being, mind avatared in all its matter, on a broad avenue winding through a city of blue trees with bright red foliage and living buildings growing from the soil in a multitude of forms.

The use of the term avatar for the on-screen representation of the user was coined in 1985 by Richard Garriott for the computer game Ultima IV: Quest of the Avatar. In this game, Garriott desired the player's character to be their Earth self manifested into the virtual world. Due to the ethical content of his story, Garriott wanted the real player to be responsible for their character; he thought only someone playing "themselves" could be properly judged based on their in-game actions. Because of its ethically nuanced narrative approach, he took the Hindu word associated with a deity's manifestation on earth in physical form, and applied it to a player in the game world. Other early uses of the term include Lucasfilm and Chip Morningstar's 1986 online role-playing game Habitat, and the 1989 pen and paper role-playing game Shadowrun.^{[citation needed]}

The use of avatar to mean online virtual bodies was popularised by Neal Stephenson in his 1992 cyberpunk novel Snow Crash. In Snow Crash, the term avatar was used to describe the virtual simulation of the human form in the Metaverse, a fictional virtual-reality application on the Internet. Social status within the Metaverse was often based on the quality of a user's avatar, as a highly detailed avatar showed that the user was a skilled hacker and programmer while the less talented would buy off-the-shelf models in the same manner a beginner would today. Stephenson wrote in the "Acknowledgments" to Snow Crash:

The idea of a "virtual reality" such as the Metaverse is by now widespread in the computer-graphics community and is being used in a number of different ways. The particular vision of the Metaverse as expressed in this novel originated from idle discussion between me and Jaime (Captain Bandwidth) Taaffe ... The words avatar (in the sense used here) and Metaverse are my inventions, which I came up with when I decided that existing words (such as virtual reality) were simply too awkward to use ... after the first publication of Snow Crash, I learned that the term avatar has actually been in use for a number of years as part of a virtual reality system called Habitat...in addition to avatars, Habitat includes many of the basic features of the Metaverse as described in this book.