A great uncle is the brother of the great nephew's grandfather or grandmother.
Your nephew's son isyour great nephew. You are his great aunt or great uncle.
You are your great nephew's great aunt if you are a woman, or his great uncle if you are a man.
not to be complicated , but if you have an uncle--> he has a nephew--> as you can see that's not complicated . And if you ask what is a uncles NEPHEW related to an uncles grandfather. in what way ....i would say the nephew is is the great gandfathers great grandson.
Your nephew's daughter's son is your great grand nephew (or great great nephew). You are his great great aunt if you are a woman, or his great great uncle if you are a man.
To your uncle, you are his niece or nephew.
Your nephew's daughter is your great niece. Her son is your great great nephew. You are his great great aunt (if you are a woman) or his great great uncle (if you are a man).
Your uncle is your child's great uncle and your grandchild's great great uncle. Your grandson is your uncles great great nephew.
You are a great great Aunt (or Uncle) to the grandson of your Nephew.
The uncle's nephew would be first cousins with the uncle's children. So the nephew would be a first cousin twice removed with the great granddaughter.
You are your nephew's uncle, or aunt, and his son's great uncle, or great aunt. Your nephew's son is your great nephew.
Your niece's son is your great nephew. You are his great aunt or great uncle.
Your great uncle's wife is your great aunt. Her nephew is either the son of one of her siblings, in which case he is not related to you, or he is the son of one of your great uncle's siblings. He could then be your father or one of your parent's brothers.