Damage part of an upright piano (3)
I believe the answer is:
rip
'damage part' is the definition.
'rip' can be an answer for 'part' (thesaurus). I'm not certain of the 'damage' bit.
'of an upright piano' is the wordplay.
'of an' becomes 'ir' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'upright' is a reversal indicator (in a down clue, letters go up).
'piano' becomes 'p' (musical abbreviation).
'ir' reversed gives 'ri'.
'ri'+'p'='RIP'
Can you help me to learn more?
(Other definitions for rip that I've seen before include "death wish" , "Letters for the deceased" , "Letters on a grave stone" , "Tear; rough water" , "found on grave?" .)