German industrial region (4)
I believe the answer is:
ruhr
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">german industrial region</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 ruhr that I've seen before include "Herman industrial area" , "German industrial region" , "German river flowing into the Rhine" , "Traditional region of German heavy industry" , "Dortmund area?" .)