Earlier quoted context omitted.
That is interesting. In many English speaking cultures children will informally refear to their mother's parents and father's parents by different names even if formally they are both "grandmother", "grandfather" or "grandparent". I like that in China they formalised the names.
Scandinavian languages have the same. »Mormor« (lit. mum mum) means maternal grandmother, while »farmor« (lit. dad mum) means paternal grandmother. Unfortunately, it doesn't appear to continue beyond that (so no »mormormor«).
“Mormorsmor” is a Swedish word. https://svenska.se/saol/?sok=mormorsmor