Any children of your parents' siblings are your cousins.
Your father's brother's son is your first cousin and your daughter's second cousin.
I will call her niece.
sister in law
Cousins
cousin!
aunt
Are you asking what you call your brothers daughter? Well if you are your brothers daughter is called your niece.
Sister In law
A niece
Niece
A niece
That would be your Cousin.