sibling-in-law

noun6

1. •
   A relative of one's generation, separated by one degree of marriage.
2. •
   The sibling of one's spouse.
3. •
   The spouse of one's sibling.
4. •
   Co-sibling-in-law: A relative of one's generation, separated by two degrees of marriage.
5. •
   The spouse of the sibling of one's spouse.
6. •
   The sibling of the spouse of one's sibling.