Neither of these terms are defined. You also will not find the definition of 'load center' or 'panel'. What you are discussing is slang usage and the slang is normally only applicable in your area. If you wish to use the proper terminology, use switchboards, panelboards, control board, and distribution boards. In the case of service equipment, 'switch gear' is not defined but enclosed service equipment is proper.SEO said:. . . the term subpanel is used. I think by the definition of a feeder the correct term would be feederpanel.