Church choral piece (5)
I believe the answer is:
motet
'church choral piece' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for motet that I've seen before include "Religious choral composition" , "Piece for choir" , "Short sacred choral piece" , "Unaccompanied choral composition with sacred lyrics" , "Anthem or church cantata" .)