Music which may be seen and read (8)
I believe the answer is:
serenade
'music' is the definition.
(serenade is a kind of music)
'may be seen and read' is the wordplay.
'may' indicates an anagram (I've seen 'might' mean this (I've seen this in other clues)).
'and' is a charade indicator (letters next to each other).
'seen' after 'read' is 'readseen'.
'readseen' is an anagram of 'SERENADE'.
'which' acts as a link.
(Other definitions for serenade that I've seen before include "Piece sung beneath beloved's window" , "Suitor's song" , "Sing (for someone on a balcony?)" , "Sing to (lover)" , "Song to a lover" .)