In modern language, an avatar is a computer-generated body or figure, controlled by a person via a digital device. It can be a computer animation image in a virtual reality environment or a robot in the real world. Avatars are most commonly found in the form of icons or moving images that represent a specific person on social networks, video games, Internet forums, and elsewhere: most often, it is a visual manifestation of a person with which one can interact in real-time.
An avatar is used to personalize a user. It reflects and/or visualizes a feature of the user, and creates a first impression. Scholars have considered avatars as "another self in the virtual world"  with the individual's characteristics or as an alter ego. They have focused on the value-expressing features of avatars and how people represent their values and attributes (though rarely their thought streams) in contexts such as social networks.
The word "avatar" has been borrowed from Hinduism, where it means a very rare being with no karma who takes human form to help people. According to the Hindu idea, the avatar was also considered a manifestation of gods in this world. New Media scholar B. Coleman points out that, similarly, in the virtual context, an avatar embodies a person that is projected into the digital world, “Instead of a god descending into mortal guise, we find people mediated by a computer network represented by figures composed of animation and automation - speed and light as it were.” 
In the digital setting, the term "avatar" was first used in 1985 in the computer game Ultima IV (Ultima IV: Quest of the Avatar), where players were represented in the virtual world by a visual image. The term was later used in the role-playing game Shadowrun (1985) and the online game Habitat (1987). The rapid development of the Internet made it possible to use avatar features outside of virtual games.
Suh, K.-S., Kim, H., & Suh, E. K. (2011). What If Your Avatar Looks Like You? Dual-Congruity Perspectives for Avatar Use. MIS Quarterly, 35(3), 711–729.
Coleman, B. (2011). Hello Avatar: Rise of the Networked Generation. MIT Press.
(Authored by Kitija Katrina Liepa)