There is no relationship. You do not share a common ancestor. The connection is simply through marriage.
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 relationship. You do not share a common ancestor. The connection is simply through marriage.
Sisters is a noun. Sisters is plural; the singular form is sister. Sister is a common noun, meaning the word can refer to any female sibling, not a specific one. Sister is a concrete noun also, meaning you can see a sister. Lastly, the possessive form of sisters is sisters'. The possessive form of sister is sister's. See the examples below: My only sister is my best friend. My two sisters are my best friends. My only sister's boyfriend gave her a ruby heart for Valentine's Day. Here the boyfriend belongs to my only sister. My two sisters' husbands are good men. Here husbands belong to my two sisters. MMP -- English teacher
Your sister's husband is your children's uncle. They are his nieces and nephews.
Sister in law
Many widows who have not remarreid and who are close to their sisters-in-law continue to consider them to be sisters-in-law. If the widow remarries, that can create a more complicated situation and they may be called "former sisters-in-law," or "the sister of my late husband."
There are many purposes of sister rings. Purposes of sister rings include wanting to honor one's sister, wanting to give a gift to one's sister, and wanting to display the relationship between sisters.
Your sister's son is your nephew.
Your kids and my sister's husband bear no relationship to each other. It is extremely unlikely that they even know each other.
Sister's means belonging to her, for example - This is my sister's shirt. And sisters is two or more, here's another example- I have five annoying sisters. So that's the differenve between sister's and sisters.
It is simply not true that a majority of the wives and their husbands' sisters don't get along and are mostly at loggerheads. Some women are like that whether they are sister-in-law or not. It has more to do with personalities and culture.
Your sister's daughter would be considered your niece.