Your granddaughter is your brother's grand niece (or some would say, great niece).
You would be 2nd cousins, assuming that the brother's wife's granddaughter is also the brother's granddaughter. If the granddaughter is not the granddaughter of the brother, there is no relationship.
Your brothers granddaughter is your grandniece.
Your granddaughter is your brother's grand niece (or some would say, great niece).
Your brother's daughter is your niece and his granddaughter is your great niece.
Your grandfather's brother is your great uncle. Your great uncle's daughter's daughter (his granddaughter) is your second cousin.
Your brother's granddaughter is your great niece and you are her great uncle if you are a man, or her great aunt if you are a woman..
You would call your father's brother's granddaughter's son your second cousin. In family terms, your father's brother is your uncle, his granddaughter is your cousin, and her son is your second cousin.
Your sisters grandson would be your grandnephew.
Your wife's brother is your brother-in-law. His son's daughter is his granddaughter and your child's first cousin, once removed, but is not related to you. You can refer to her as "my brother-in-law's granddaughter."
Your grandfather's brother's granddaughter is your second cousin.
No. The sister is a relation, and her husband is an in-law. The husband's brother is no biological relation either. Therefore, the great granddaughter of the husband's brother is not a relation.
great uncle