Stadiums (6)
I believe the answer is:
arenas
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stadiums</span>' is the definition.<br/ ><span class="explanation-format__explanation">('arena' can be a synonym of 'stadium')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for arenas that I've seen before include "Structures for open-air events" , "A snare for central parts of amphitheatres" , "Areas of endeavours" , "Stadia" , "Spaces for sports events" .)