> Does the spec need a term to indicate this relation in the general
> case? I agree that the term "overlap" is fraught with other senses,
> and should probably be avoided.
> 

I have raised this terminological issue here:

https://www.w3.org/Bugs/Public/show_bug.cgi?id=24290

and we'll see what we can come up with.

Michael Kay
Saxonica