Tier (3)
I believe the answer is:
row
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tier</span>' is the definition.<br/ ><span class="explanation-format__explanation">(eg a row of seats at a theatre)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for row that I've seen before include "Paddle" , "One of the ranks" , "Fight in a queue?" , "Fall out" , "Quarrel about the tier" .)