Bill for publicity (6)
I believe the answer is:
poster
This clue might be a double definition.
'bill' is the first definition.
(I know that bill can be written as poster)
'publicity' is the second definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'for' acts as a link.
Can you help me to learn more?
(Other definitions for poster that I've seen before include "bulletin board participant" , "surfer who leaves messages on boards?" , "Printed advert" , "'Notice, placard (6)'" , "Person who sends" .)