Arrangement of ornamental edges? Not edges! (5)
I believe the answer is:
order
'arrangement' is the definition.
(I know that order is a type of arrangement)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for order that I've seen before include "Tell - regulate" , "Command harmony" , "Arrangement; command" , "American helping" , "Regulation" .)