Plenty of cello tone (3)
I believe the answer is:
lot
'plenty' is the definition.
(thesaurus)
'of cello tone' is the wordplay.
'of' says the answer is hidden in the clue.
'LOT' is hidden within 'cello tone'.
(Other definitions for lot that I've seen before include "Survivor in Sodom" , "Nephew of Abraham - batch" , "A person's luck" , "Destiny - biblical character - Polish national airline" , "Great deal; French river" .)