Batman and Robin, maybe with time for some poetry (6,7)
I believe the answer is:
heroic couplet
'poetry' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for heroic couplet that I've seen before include "Classical verse form" , "bit of verse" , "Poetic form used by Chaucer -- ochre poultice (anag)" , "two lines by Chaucer" .)