A public delivery (7)
I believe the answer is:
recital
'a public delivery' is the 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?
This is all the clue.
Can you help me to learn more?
(Other definitions for recital that I've seen before include "Article about musical entertainment" , "Soloist's performance" , "Public performance by a solo musician" , "(Usually solo) concert" , "Performance, usually musical" .)