From 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.
From 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]