Conductor (9)
I believe the answer is:
electrode
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">conductor</span>' is the definition.<br/ ><span class="explanation-format__explanation">(electrode is a kind of conductor)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for electrode that I've seen before include "Conducting point by which electric current enters or leaves" , "Conducting contact" , "Conductor (eg, in battery)" , "Conductor by which current enters" , "Conductor for electricity as it enters or leaves" .)