Cry heard in auditorium before soldier enters (6)
I believe the answer is:
encore
'cry heard in auditorium' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'before soldier enters' is the wordplay.
'before' becomes 'ere' (poetic term for 'before').
'soldier' becomes 'nco' (non-commissioned officer).
'enters' means one lot of letters goes inside another.
'ere' going around 'nco' is 'ENCORE'.
Can you help me to learn more?
(Other definitions for encore that I've seen before include "Bonus" , "Bis!" , "Please play some more!" , "Call for additional item" , "Cry from the audience for more" .)