Theatrical utterance possibly said to echo (5)
I believe the answer is:
aside
'theatrical utterance' 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?
'possibly said to echo' is the wordplay.
'possibly' indicates an anagram.
'to echo' becomes 'e' (phonetic alphabet: alpha, bravo, charlie etc.).
'said' anagrammed gives 'asid'.
'asid'+'e'='ASIDE'
Can you help me to learn more?
(Other definitions for aside that I've seen before include "Line spoken to theatre audience" , "Words spoken apart in an undertone" , "Away from main action" , "In reserve -- confidential remark" , "Actors comment to his audience" .)