The name of the login account given full and complete access to all system resources or the “superuser”. Also used to describe the directory named ”/“as in, “the root directory.”
One can become root by either logging in as user “root” or by typing “su” within a normal user's login session. The root password is required to become root.
Tip: typing “su - ” instead of “su” actually changes the login session to that of root; the session behaves the same as though user root had actually logged in to begin with.