Glad to have piano let out (7)
I believe the answer is:
pleased
'glad' is the definition.
(similar in meaning)
'piano let out' is the wordplay.
'piano' becomes 'p' (musical abbreviation).
'let out' becomes 'leased' (as in leasing or letting out property).
'p'+'leased'='PLEASED'
'to have' acts as a link.
(Other definitions for pleased that I've seen before include "Feeling satisfaction" , "like Punch?" , "Glad" , "Euphoric" , "Happy, satisfied" .)