Rank individual numbers in pieces of music (8)
I believe the answer is:
baroness
'pieces of music' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'rank individual numbers' is the wordplay.
'rank' becomes 'baron' (I have seen 'Noble rank' mean 'baron' so perhaps 'rank' could also mean 'baron').
'individual numbers' becomes 'ess' (I can't explain this - if you can you should give a lot more credence to this answer).
'baron'+'ess'='BARONESS'
'in' is the link.
Can you help me to learn more?
(Other definitions for baroness that I've seen before include "Lady peer" , "Noble" , "Woman life-peer" , "Female life peer" , "Titled lady" .)