The daughter of your mother's sister is your first cousin.
Your sister's daughter is your niece.
The parents of a husband are not related to the parents of his wife. Answer There is no relationship at all as there is no blood tie with either of the mothers. If however the mother in law was the mothers sister, then that would be the relationship i.e. sister.
Niece. Your mother has children, you and your sister. So your mother's daughter is your sister. When she has a daughter, this is your niece.
cousin
Your sister's daughter is your niece, so you are her aunt or her uncle.
Mothers sister is aunt and son is cousin so daughter wouldn't that be a niece
no....because she is a sister for you
Your daughter-in-laws sister. There is no relationship as you do not share a common ancestor.
Your mother's sister is your aunt and her daughter is your first cousin.
Your sister's daughter is your niece. Your niece's husband is not related to you.
The relationship to you would be your cousin !
Your Niece.