Ring our lot about piano piece (4)
I believe the answer is:
opus
'piece' is the definition.
(I know that piece can be written as opus)
'ring our lot about piano' is the wordplay.
'ring' becomes 'o' (letter resembling a ring).
'our lot' becomes 'us'.
'about' is a charade indicator (letters next to each other).
'piano' becomes 'p' (musical abbreviation).
'us' put after 'p' is 'pus'.
'o'+'pus'='OPUS'
(Other definitions for opus that I've seen before include "Musical composition in the soup" , "Composition - magnum __" , "Musical piece" , "(Numbered) musical composition" , "A Latin work" .)