I have heard the term "bones" and phrase "build the bones" used in the context of the family editor in the past. In fact some of the earlier Revit Technology Corporation (RTC) and Autodesk Family Editor documents have used the term too, perhaps for the first time even. Lately over the last year or two I've been expanding on the metaphor.
Bones = Reference Planes
Muscle = Dimensions, Labels/Parameters, Automatic Sketch Dimensions
Skin = Solids/Voids and Symbolic Linework
If you properly define the "bones" first and then connect the "muscle(s)" to them you'll find that your "skin", once anchored to the bones, will go wherever the muscle tell the bones to go. I just picture my arm and in fact I usually hold it up and move it at the elbow while I mention it in classes. A properly defined family will behave as consistently as your arm does, unless you manage to do it harm skiing?
Too clinical? Squeamish? Sorry!