[wruza]

[super]<class> and [sub]<class>s (or simply 'subitems'). Like in superview and subviews, group and subitems, superclass and subclass.

[DonHopkins]

Yes, that's a great example of why it's always good to use names that describe the nature of the relationship, because nodes can exist in multiple hierarchies at once, that have no topological relationship to each other, like a view hierarchy and a class hierarchy.

A Button can be inside a Panel, but not a subclass of Panel.

A Button can be a subclass of Control, but not inside a Control.

Having two types of parents (view and class) is different that having two parents (mommy and daddy).