Quiet on first stage for the mail (7)
I believe the answer is:
postage
'the mail' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'quiet on first stage' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'on first' becomes 'o' (1st letter of 'on').
'p'+'o'+'stage'='POSTAGE'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for postage that I've seen before include "Mailing cost" , "It could be first-class" , "Delivery cost" , "Amount paid to mail" , "Cost of corresponding" .)