'Bretheren, Odysseus has a sad air' (8)
I believe the answer is:
threnody
'air' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for threnody that I've seen before include "Dirge" , "Do try hen (anag.)" , "A song of lamentation" , "A lament" .)