Afternoon paper? (4)
I believe the answer is:
exam
This clue could be a double definition.
'afternoon' is the first definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'paper?' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for exam that I've seen before include "Student test" , "Test (abbrev.)" , "(Academic) test" , "Set of questions evaluating skill or knowledge, in short" , "'Test, in short (4)'" .)