– If A is B’s child and B is C’s child, then A is C’s grandchild, right?

– Right.

– So if A is B’s little sister and B is C’s little sister, then A is C’s grand little sister, right?

– Hmm… I can almost believe this: if A is B’s pet and B is C’s pet, then A is C’s grand pet. But “grand little sister,” I don’t know about that.