What is ‘wheel’?

I came across a very interesting article titled Why GNU su does not support the ‘wheel’ group. I have seen wheel under Red Hat Enterprise Linux but never understood why such a special group existed. I didn’t even bother to find out. But the aforementioned article made me curious. So off to Google. The wheel Group was the one I was looking for. According to it, wheel is a special group which in conjunction with settings for su determines which users are allowed to use the su command. So if you have a wheel group set up then you may configure su so that only members of wheel are able to use the command. As one commentor on the post put it, this creates a circle of trust, and is called wheel.