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.