Chimney or funnel (10)
I believe the answer is:
smokestack
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">chimney</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that smokestack is a type of chimney)</span><br/ ><br/ >'<span class="explanation-format__original">funnel</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for smokestack that I've seen before include "Ship's funnel" , "industrial feature" , "chimney" .)