Your aunt's brother is either your father or your uncle. If you are a girl, you are always your aunt's niece.
Niece is to nephew as sister is to brother.
Your niece.Your brother's daughter would be your niece and you'd be her uncle or aunt. Your sister's daughter would also be your niece. If your sibling had a son, he would be your nephew.
Nothing. Your niece in law. Your brother in laws niece.
Aunts usually address their nieces by name
It would be your second cousin because your mothers uncle would be your great uncle his brother would still be your great uncle because he is still your mum's brother so then his daughter would your mum's niece and your cousin.
your niece
Your granddaughter is your brother's grand niece (or some would say, great niece).
Your granddaughter is your brother's grand niece (or some would say, great niece).
sisterNo it would be Niece is to Nephew as Sister is to Brother. Niece and sister are both female, nephew and brother are both male.
Your husband's niece is your niece, too. You and your husband are her aunt and uncle. Your brother is not related to a niece of yours who is the daughter of your husband's sibling.
You are your niece's aunt, if you are a woman.Any of your sisters who are not your niece's mother are also her aunts.The sisters of your niece's parent who is not your sibling are also her aunts.
Your grandfather's sister is your great aunt.