Your brother's daughter and your daughter are first cousins to each other.
Your brother's daughter and your daughter's daughter (your granddaughter) are first cousins, once removed, to each other.
Your brother's daughter is your niece and you are her uncle.
Your brother's daughter is your niece..and you are her AUNT.
Great Niece.
YES
You are their aunt or aunt by marriage.
That would be her great uncle I suppose. Common sense.
First cousins twice removed.
Your younger brother's wife's sister's daughter would be your son's cousin.
Your brother would be your son's daughter's great uncle and your son's daughter would be your brothers great niece! Hopefully that makes sense :)
Your sister's daughter is your niece and you are her aunt (if you are a woman) or her uncle (if you are a man).
Are you asking what you call your brothers daughter? Well if you are your brothers daughter is called your niece.
Daughter is the opposite of son.
a relationship between brothers should be sacred and good....