Pressure on after time in war zone (7)
I believe the answer is:
theatre
'war zone' is the definition.
(theatre of war is an area of confrontation in war)
'pressure on after time' is the wordplay.
'pressure' becomes 'heat' (I've seen this in another clue).
'on' becomes 're' ('on' can be mean 'with reference to').
'after' says to put letters next to each other.
'time' becomes 't' (abbreviation).
'heat'+'re'='heatre'
'heatre' put after 't' is 'THEATRE'.
'in' is the link.
(Other definitions for theatre that I've seen before include "Where audiences may be present" , "Scene of operations or dramatic performances" , "Drama in general" , "Criterion in London, say" , "Hospital operating room - playhouse" .)