In David Copperfield, he has the key to the piano (4)
I believe the answer is:
heep
'in david copperfield' is the definition.
I know nothing about this answer so I can't tell whether this works.
'he has the key to the piano' is the wordplay.
I cannot really see how this works, but
'he' is within the answer.
'key' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
'piano' could be 'p' and 'p' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for heep that I've seen before include "lawyer's clerk" , "Uriah . . . . , Dickens hypocrite" , "Uriah . . . ., arch-hypocrite in 'David Copperfield'" .)