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" .)

I've seen this clue in The Telegraph.

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