kibling
When a brother and sister, marry another set of sister and brother. Thus, marrying their in-laws. Their kin folk would usually be called cousins. But in the case of a kibling, they are more then cousins.
they are sibling-cousins. (KIBLING)
they are sibling-cousins. (KIBLING)
My mom's sister married my dad's brother. Their not just cousins, but not quite siblings. They're kiblings!