Supply arrangement (5)
I believe the answer is:
order
This might be a double definition.
'supply' is the first definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'arrangement' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for order that I've seen before include "Command; sequence" , "Annual film award (5)" , "Select from menu" , "Rank" , "an answer to all clues, initially" .)