...niece.
Your brother or sister's daughter is called 'your niece.'
Your sister's daughter is your niece.
Your sister's daughter is your niece. You are her aunt (if you are a woman) or her uncle ( if you are a man).
niece
Cousin.
Your father's sister's daughter is your cousin. Therefore, your father's sister's daughter's daughter would be your cousin's daughter. In genealogical terms, she would be your first cousin once removed.
its called a niece
1st Cousin
he has two. his older sister is called lynne and his younger sister is called joanne.
If the brother-in-law's daughter is also your sister's daughter, she would be a niece. Otherwise, there is no relationship.
I know of no Egyptian goddess called Kemse-Mies, but Bast was daughter of Ra and any other daughter of Ra could rightfully be called her sister.
If it is your brother's child, she would be your "niece." If the daughter is not fathered by your brother, then she is your "sister in law's daughter"