Area for new part of stage (5)
I believe the answer is:
apron
'part of stage' is the definition.
(I've seen this before)
'area for new' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'for' becomes 'pro' (I've seen this before).
'new' becomes 'n'.
'a'+'pro'+'n'='APRON'
(Other definitions for apron that I've seen before include "Pinnie" , "standing" , "Put on to protect" , "something befitting kitchen-sink drama?" , "Kitchen garment or airfield area" .)