Sepulchral monument (4)
I believe the answer is:
tomb
'sepulchral monument' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tomb that I've seen before include "Place for the burial of a corpse" , "Catacomb" , "Place of burial, grave or vault" , "Sepulchral monument" , "Burial chamber" .)