Order mixer only to be added? (6)
I believe the answer is:
notice
'order' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for notice that I've seen before include "Take cognisance of, observe" , "Sign posted in a public place" , "See; advert" , "Advance warning of an event" , "Warning - observe - review" .)