Piano seen in old time musical drama (5)
I believe the answer is:
opera
'musical drama' is the definition.
(I've seen this before)
'piano seen in old time' is the wordplay.
'piano' becomes 'p'.
'seen in' is an insertion indicator.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'time' becomes 'era' (I've seen this before).
'o'+'era'='oera'
'p' going within 'oera' is 'OPERA'.
(Other definitions for opera that I've seen before include "Fidelio for instance" , "Eg, Il trovatore" , "Tosca, for example" , "Eg, Rigoletto" , "musical performance" .)