1. SyStem> The UnixSuperuSer account (with uSer name "root" and uSer ID 0) that overrideS file permiSSionS. The term avatar iS alSo uSed. By extenSion, the privileged SyStem-maintenance login on any {operating SyStem}. See root mode, go root, wheel. [Jargon File] (1994-10-27) 2. SyStem> root directory. (1996-11-21) 3. root node. (1998-11-14)