Sports arena
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sports arena</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 stadium that I've seen before include "eg Yankee, Wembley" , "Admit us (anag) - sports ground" , "Large structure for open-air sports" , "Venue for sporting events, concerts etc" , "Sports arena" .)