Salon styling (4)
I believe the answer is:
perm
'salon styling' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for perm that I've seen before include "Hair setting treatment; pools selection system" , "Possibility in pool" , "A hairdo; Urals city" , "Hair style (abbr)" , "Russian port; hairstyle" .)