American piano used in parties raises questions (8)
I believe the answer is:
suspects
'questions' is the definition.
(suspecting is a kind of questioning)
'american piano used in parties raises' is the wordplay.
'american' becomes 'US' (United States).
'piano' becomes 'p' (musical abbreviation).
'used in' is an insertion indicator.
'parties raises' becomes 'sects' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'us'+'p'='usp'
'usp' placed within 'sects' is 'SUSPECTS'.
Can you help me to learn more?
(Other definitions for suspects that I've seen before include "Imagines to be true" , "Mistrusts" , "They're believed to be guilty" , "Those under investigation" , "Considers or believes likely" .)