Sibling's child (6)
(Other definitions for nephew that I've seen before include "Has a duty (to do something)" , "Brother's/sister's son" , "Family relative" , "Edward V to Richard III relation" , "Sibling's son" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sibling's child</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for niece that I've seen before include "Young female relative" , "Brother's girl" , "A sibling's daughter" , "Family relation" , "girl further down the line" .)