Wave setting, at times (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
arena
'wave setting at times' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for arena that I've seen before include "battlefieId" , "Stadium - battlefield" , "Playing area" , "Sphere of action" , "O2, for example" .)