There is no relationship. You do not share a common ancestor. The connection is simply through marriage.
English doesn't have a concise term for this specific relationship. "My daughter-in-law's sister" (or "my sister's father-in-law", depending on who's describing whom) is about the shortest phrase that captures the essentials of the relationship.
There is no relationship. You do not share a common ancestor. The connection is simply through marriage.
He is brother your brother in law.
Your husband's sister is your sister in-law.
How could the relationship between Pip and Biddy be described?
sister in law
Your brother would call your husbands sister by her first name. Or, "my (sibling's) sister in law.
Let's see if we can unravel this. Your sister's husband's father's brother is your sister's husband's uncle. The uncle's daughter is your sister's husband's cousin. There is no relationship to your sister, unless your sister wants to call her a cousin-in-law. To break it down to its simplest terms: She is your brother-in-law's cousin and no relationship to you.
There is no common ancestor, so you aren't really related. Related by marriage is one way to describe the relationship.
Your Sister-in-law
nothing
They are Brother & Sister.
you call her your daughter's husband's sister