Telegraph line? (9)
I believe the answer is:
editorial
'telegraph line?' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for editorial that I've seen before include "paper item" , "Article written" , "Article that states a newspaper's opinion" , "leader, perhaps" , "considered view on paper" .)