Instrument that is properly one's forte? (5)
I believe the answer is:
piano
This could be a double definition.
'instrument that is properly one's' is the first definition.
'piano' can be an answer for 'instrument' (piano is a kind of instrument). I'm not certain of the remainder of the definition.
'forte?' is the second definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for piano that I've seen before include "Musical instrument - play quietly" , "Softly, musically speaking" , "p (mus.)" , "Soft - musical instrument" , "Instrument with ivories" .)