Love piano accompaniment for American piece of music (4)
I believe the answer is:
opus
'piece of music' is the definition.
('opus' can be a synonym of 'piece of music')
'love piano accompaniment for american' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'piano' becomes 'p'.
'accompaniment for' means one lot of letters go next to another.
'american' becomes 'us'.
'o'+'p'+'us'='OPUS'
(Other definitions for opus that I've seen before include "Composer's work" , "Major work" , "Work (mus.)" , "Artistic work" , "Musical composition in the soup" .)