Note on musical furniture (5)
I believe the answer is:
chair
'furniture' is the definition.
(I know that chair is a type of furniture)
'note on musical' is the wordplay.
'note' becomes 'c' (musical note).
'on' says to put letters next to each other.
'musical' becomes 'hair' (1960s musical).
'c'+'hair'='CHAIR'
(Other definitions for chair that I've seen before include "Preside, guide meeting" , "Top seat of committee" , "Seat (of learning?)" , "Lead" , "Item of furniture (which can be addressed!)" .)