Your sister's daughter is your niece. If you are a woman, you are your niece's aunt; if you are a man, you are your niece's uncle.
Your sister's son is your nephew.
Your niece
Your brothers ( or sisters ) daughter is your ( niece )
Your brother or sister's daughter is called 'your niece.'
If she is your sisters daughter then she is your neice :)
I don't know what they are called in English, but in Hindi, your daughter in law's parents would be called "Samdhees".
she would be your grandmals sisters sons daughter =)
She is your niece.
A niece. How could you not know that
Because they are both female, and that is the way the English language does it.
It is not her daughter is one of her sisters:)
In the genealogical sense, the English language has no relationship called "great sister."
Putravadhu (son's wife) is called Daughter-in-Law in English