avatar:n. Syn.   1. Among people working on virtual reality and {cyberspace} interfaces, an "avatar" is an icon or representation of a user in a shared virtual reality. The term is sometimes used on {MUD}s. 2. [CMU, Tektronix] {root}, {superuser}. There are quite a few Unix machines on which the name of the superuser account is `avatar' rather than `root'. This quirk was originated by a CMU hacker who disliked the term `superuser', and was propagated through an ex-CMU hacker at Tektronix.