What is the origin and definition of the term "overriders"?

[Zaptastic]

In my nursing skills lab, we have a very detailed list of health assessment performance criteria that we will be tested on. There is a list of "overriders" like 1. Obtains physician's orders, 2. Obtains correct equipment, 3. Washes hands, 4. Applies principles of aseptic technique, etc ...

I understand that these are critical steps that supersede everything else, but where did the term "overriders" come from and is it a standard term in the medical field? I couldn't find it in Tabers, a Google search for "nursing overriders", or in a search here at AllNurses. I am just wondering if other schools use that term or not. Thanks for any insight.