[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.