River of Devon (3)
I believe the answer is:
exe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">river of devon</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for exe that I've seen before include "Somerset/Devon river" , "Banker" , "River in SW UK" , "Devon river" , "River of southwest England" .)