Lawyers about to take part in song (9)
I believe the answer is:
barcarole
'song' is the definition.
(barcarole is a kind of song)
'lawyers about to take part' is the wordplay.
'lawyers' becomes 'bar' (the bar can mean the legal profession).
'about' becomes 'ca' (circa).
'to take part' becomes 'role' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'bar'+'ca'+'role'='BARCAROLE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for barcarole that I've seen before include "musical composition" , "Gondolier's song" , "Venetian boating song" , "music of Venice" , "Italian song" .)