Serenity's heard - Moonlight Sonata perhaps (5)
I believe the answer is:
piece
'moonlight sonata perhaps' is the definition.
I can't tell whether this defines the answer.
'serenity's heard' is the wordplay.
'serenity' becomes 'peace' (synonyms).
'heard' indicates a 'sounds like' (homophone) clue.
'peace' sounds like 'PIECE'.
Can you help me to learn more?
(Other definitions for piece that I've seen before include "Musical work; bit" , "Artwork" , "man on board" , "Scrap - musical work" , "Chessman - part - firearm" .)