Nut provided by Patricia Cornwell (5)
I believe the answer is:
acorn
'nut' is the definition.
(I've seen this in another clue)
'provided by patricia cornwell' is the wordplay.
'provided by' indicates the answer is hidden within the clue (the answer is provided within the clue).
'ACORN' is hidden in the letters of 'patricia cornwell'.
(Other definitions for acorn that I've seen before include "Potential oak" , "Fruit of the oak tree" , "cup's content" , "Might source" , "Model in stone" .)