wheel

wheel n.  [from slang `big wheel' for a powerful person] A
   person who has an active {wheel bit}.  "We need to find a wheel
   to unwedge the hung tape drives."  (See {wedged}, sense 1.)
   The traditional name of security group zero in {BSD} (to which
   the major system-internal users like {root} belong) is
   `wheel'.  Some vendors have expanded on this usage, modifying
   UNIX so that only members of group `wheel' can {go root}