your 2nd cousin, or maybe your 2nd cousin once removed.
great second cousin
jew face
second-cousin
Your child and your niece are first cousins to each other. Your child and your niece's child are first cousins, once removed.
Your child and your nephew are first cousins. Your child and your great nephew are first cousins, once removed.
Your uncle's granddaughter and your child are second cousins.
First cousin once removed.
You and the child of your second cousin are second cousins, once removed.
Your first cousin's child and your child are second cosins. Your first cousin's grandshild and your child are second cousins, once removed. Your second cousin's child and your child are third cousins. Your second cousin's grandchild and your child are third cousins, once removed.
Your second cousin's siblings are also your second cousins. The children of your second cousins are your second cousins, once removed.
Your child and your great nephew's parents would be first cousins. Their children would then be second cousins. And if they have children, they will be third cousins.
They would be third cousins, I don't believe that's illegal in any state, only first cousins, and in some states not even that. Being that distant of relation, there is no worry of their children having birth defects. They would be third cousins and I don't believe any state outlaws this. Some states do not even outlaw first cousin marriages. Being so distantly related, there is no worry of their children having defects of any kind.
Your daughter and your sister's child are first cousins. Your daughter and your sister's grandchild are first cousins, once removed.