[1] : Jargon File (4.3.1, 29 Jun 2001)

superuser n. unix syn. root, avatar. this usage has spread to
   non-unix environments; the superuser is any account with all wheel
   bits on. a more specific term than wheel.


see also:
root avatar wheel 

[2] : The Free On-line Dictionary of Computing (27 SEP 03)

superuser
     
        unix synonym root, avatar.  this usage has spread to
        non-unix environments; the superuser is any account with all
        wheel bits on.  a more specific term than wheel.
     
        jargon file
     
     
see also:
root avatar wheel jargon file 

Superuser >> S Words
Superuser, definition of term: Superuser
superuser_pag1.html