She is your aunt. This is true in most traditions. English does not distinguish between an aunt by marriage (father's brother's wife) or an aunt by blood relation (father's sister).
Your grandma's brother is your great uncle, his wife is your great aunt.
Your grandmother's brother's wife is your great aunt.
Your mother's brother's wife is your aunt.
Aunt
Cousin
Aunt
Your father's brother's son is your first cousin and your daughter's second cousin.
your 5th cousin
granddaughter
Cousins
cousin!
aunt
Are you asking what you call your brothers daughter? Well if you are your brothers daughter is called your niece.
A niece
Niece
A niece
That would be your Cousin.
natini