Elton John's instrument (5)
I believe the answer is:
piano
'elton john's instrument' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for piano that I've seen before include "Stringed instrument - to be played quietly" , "In musical notation, this means softly" , "Softly (mus.)" , "p (mus.)" , "Softly, musically speaking" .)