Khartoum's river (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">khartoum's river</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for nile that I've seen before include "River associated with Cleopatra" , "long-distance runner in Africa" , "River that's Blue and White" , "River of eastern Africa" , "River (which is originally blue and white)" .)