Where in the 2011 nec does it mention subfed or subpanel ?
You will find "subpanel" mentioned in 409.2.
You won't find "subfed" mentioned anywhere.
409.2?
And in that definition, the word has nothing to do with how it is normally used in the field.No longer there... 2011 had the 409.2 now ithe word subpanel is mentioned in definitions of industrial control panels