Bishop's vestment (3)
I believe the answer is:
alb
'bishop's vestment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for alb that I've seen before include "Clerical gown" , "Priest's long white sleeved vestment" , "ecclesiastical garment" , "White clerical garment" , "the vicar might put on?" .)