Your son and your grand niece are first cousins, once removed.
Explanation:
Find the common ancestor, in this case, your parents. Your parents have two children, you and your sister or brother. Your sister or brother has a son or daughter. This child would be your nephew or niece and your son's 1st cousin. A daughter of your nephew or niece is your grand-niece, thus your son's 1st cousin once removed.
Note: Your grand-niece and your son's child would be 2nd cousins.
Hierarchy:
1. Any people
2. sons and daughters are siblings to each other
3. grandchildren are first cousins to each other
4. great-grandchildren are second cousins to each other
Your child and your nephew are First Cousins. Your grand nephew is the child of your nephew. Therefore your child and your grand nephew are First Cousins, Once Removed.
Your grand nephew's (great nephew's) son is your great great nephew. You are his great great uncle or aunt.
They would be first cousins, once removed.
Your son and your nephew are first cousins.
Your grand nephew is the son of your niece or nephew and thus a first cousin, once removed, to your son.
Your nephew and your great grandson are first cousins, twice removed, to each other.
Your brother's or sister's son is your nephew. Your nephew's or niece's child is your grand-nephew or grand-niece.
Your nephew and grand nephew may be parent and child. In not, then they are First Cousins, Once Removed.
you would be the child's great aunty or uncle Therefore, they would be your great niece or nephew.
Your great great nephew's child is your great great great niece or great great great nephew, depending on the sex of the child.
No. A great grand child is the child of your grandchild. The child of your grand niece is your grand niece or grand nephew, depending on the child's sex.
Your niece's child is your grand-niece or grand-nephew, and they would be a cousin to your children.
Your nephew's children are your great nephews and great nieces (or grand nephews and grand nieces).
The children of your grand nephew (or great nephew) are your great great nephews and great great nieces (depending on whether they are girls or boys).
Your niece's son is your grand-nephew. You are the child's grand aunt, or grand uncle (whichever applies).
Your nephew's daughter is your great niece and you are her great Aunt (or Great Uncle).Correction:Your nephew's daughter is your grand niece. You are her grand aunt or grand uncle.
Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.Octavian was Caesar's grand nephew who he adopted as his heir.
Your niece's son is your grand-nephew. You are the child's grand aunt, or grand uncle (whichever applies).