Seat for one (5)
I believe the answer is:
chair
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">seat for one</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for chair that I've seen before include "Single seat" , "Lead" , "Seat for one person" , "Senior academic post" , "Official position of authority" .)