Broken door acquires new piece (5)
I believe the answer is:
rondo
'piece' is the definition.
(type of musical composition)
'broken door acquires new' is the wordplay.
'broken' indicates an anagram.
'acquires' is an insertion indicator.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'door' is an anagram of 'rodo'.
'rodo' placed around 'n' is 'RONDO'.
(Other definitions for rondo that I've seen before include "Piece of music with repeated refrain" , "Musical piece with a recurring theme" , "part of a sonata" , "Music with repeated refrains" , "Donor (anag) - piece of music" .)