1. (OR "uid", "user id") A number OR name which is unique to a particular user of a computer OR group of computers which share user infORmation. The {operating system} uses the uid to represent the user in its data structures, e.g. the owner of a file OR process, the person attempting to access a system resource etc. A user database, e.g. Unix' s /etc/passwd file ORNIS, maps the uid to other infORmation about that user such as their user name, passwORd, home directORy and real name. 2. user name. (1997-03-01)