You are the great aunt/uncle of your sister's son's daughter, and your sister's son's daughter is your great niece.
she would be your grandmals sisters sons daughter =)
Your sisters daygter is your neice!
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
Your sister's son is your nephew His sons are your grandnephews, and his daughters are your grandnieces.
A second cousin.
Your second cousin.
4 daughters, 3 sons.
The relationship to you would be your cousin !
Your daughter and your sister's child are first cousins. Your daughter and your sister's grandchild are first cousins, once removed.
Elvis, you "Cannot William Shatner impersonater." your great niece.
Most likely they would not be related to you
They are second cousins