Sister's daughter, say (5)
I believe the answer is:
niece
(Other definitions for niece that I've seen before include "Family girl" , "A sibling's daughter" , "Brother's daughter" , "A sibling's child" , "Brother's girl" .)
I believe the answer is:
niece
(Other definitions for niece that I've seen before include "Family girl" , "A sibling's daughter" , "Brother's daughter" , "A sibling's child" , "Brother's girl" .)