If your sister-in-law is married to your brother or sister, her nephew may be your nephew.
Otherwise her nephew is not blood related to you, But he is related by marriage to you and he is stort of newphew in law.
There is no special name for this relation. If he calls you "uncle", which was the custom in my family for the husband of my aunts, you can describe him as your nephew unless there is some reason to make it clear that he is really your wife's nephew.Well just going to add on if you guys are really close than you guys would have nickname for each other or just use a simple name
You would call your nephew's wife "my nephew's wife." The English language does not have a relationship called niece-in-law. That is a modern construction invented by those who think there ought to be a name for that.
You could also call her "my brother's [or my sister's] daughter-in-law."
By her name. There is no name for the relationship as there is none.
Call her your nephew's wife, as that is what she is!
Your husband's nephew is also your nephew, some would add "by marriage" but that has little bearing in common usage. So the nephew's daughter is your great niece.
Your wife's niece is also your niece, and you are her uncle.
niece by marriage
Yes.
The English language has no relationship name for the wife of your great niece or great nephew.
If your sister had a son, then he is your nephew.
Your nephew's child is your great niece (if a girl) or your great nephew (if a boy).
The English language has no special name for a nephew's wife and does not consider you to be related to you. You would simply call her "my nephew's wife."
Your mother's nephew is your First Cousin.
You are your nephew's uncle if you are male, and his aunt if you are female.
Mother in-law
Either nephew or nephew in law.
My sister's son is my nephew.
Sugar Daddy
sweety