Great Grandnephew
A great grandnephew is the son of a person's grandnephew or grandniece. In other words, he is the great grandchild of one's sibling's grandchild. This relationship indicates a familial connection that is four generations removed.
A great grandnephew is the son of a person's grandnephew or grandniece. In other words, he is the great grandchild of one's sibling's grandchild. This relationship indicates a familial connection that is four generations removed.