Your niece.
Your sister's daughter is your niece and her granddaughter is your great niece.
bhagina
Your sister's daughter is your niece, her granddaughter is your "great niece"... or you could just call her by name.
you call her your daughter's husband's sister
Your daughter is your sister's niece. Your daughter's son is her great nephew.
You would call your sister's daughter your niece.
Your sister's daughter is your niece.
Your sister's daughter, to you, is your neice. (You are her aunt or uncle). If the daughter were actually a son, he would be you nephew.
You would call your sister's son your nefu and her daughter neice.
She is your niece
Your niece