wheelwheel
is the group used by OSX for the 'system' /Applications. It was present since at least
1989-03-13 in the source of BSD Unix.
Whether the connotation is 'big wheel' or 'wheel of fortune' is unclear from my sources, but membership of wheel is special.
In OS X PAM is used to set the policy that su(1)su(1)
will use. In particular, by default
only users in the admin'' or admin
wheel'' or wheel
groups can switch to UID 0
(root''). This group requirement may be changed by modifying the root
pam_group''). This group requirement may be changed by modifying the
pam_group
section of /etc/pam.d/su/etc/pam.d/su
. See pam_group(8)pam_group(8)
for details on
how to modify this setting.