Where casualties may be treated in areas of warfare (8)
I believe the answer is:
theatres
'areas of warfare' is the definition.
'theatres' can be an answer for 'areas' (I have seen 'Areas of operations ' mean 'theatres' so perhaps 'areas' could also mean 'theatres'). I am not sure about the 'of warfare' bit.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for theatres that I've seen before include "Scenes of important events, like playhouses" , "Buildings for dramatic art" , "Lecture rooms with seats rising in tiers" , "Spaces for surgery and drama" , "Performance areas" .)