Steer brilliant symposium (6)
I believe the answer is:
confab
'steer brilliant symposium' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'steer brilliant' is the wordplay.
'steer' becomes 'con' (I've seen this in other clues).
'brilliant' becomes 'fab' (short for fabulous).
'con'+'fab'='CONFAB'
Can you help me to learn more?
(Other definitions for confab that I've seen before include "Chat (informal)" , "Informal discussion (colloq.)" , "Chatter" , "natter" , "Informal conversation" .)