Fashion etiquette (4)
I believe the answer is:
form
I believe this is a double definition.
'fashion' is the first definition.
(thesaurus)
'etiquette' is the second definition.
(I've seen this before)
(Other definitions for form that I've seen before include "Make" , "Establish" , "Class; schedule" , "Group of schoolchildren < > construct" , "Printed document with spaces to write" .)