Your grandson and your great nephew are second cousins to each other.
Your father's great grandson could be your grandson, or your great nephew.
Your grandson is your sister's great nephew and she is his great aunt.
You grandson is great great nephew to your uncle. You uncle is great great uncle to your grandson
You grandson is great great nephew to your uncle. You uncle is great great uncle to your grandson
Great Grand Nephew
great great nephew and u wud be a great great aunt... i think :)
The great grandson of your sister is your great great nephew. You are his great great aunt or great great uncle.
You great aunt's grandson would be your great-great cousin.
She would be his Great Aunt
great great nephew and u wud be a great great aunt... i think :)
Your nephew is the son of your sibling and a first cousin of your childrenYour grand nephew (or great nephew) is the grandson of your sibling and a second cousin of your grandsonYour great great nephew (or great grand nephew) is the great grandson of your sibling and is a 2nd cousin once removed of your grandson
Your sister's son is her grandson and your great nephew. Some use the term "grand nephew."