Thick slice (4)
I believe the answer is:
slab
'thick slice' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for slab that I've seen before include "Broad, thick piece of wood, stone" , "Mortuary table" , "Thin flat stone" , "Thick flat piece of stone" , "Flat piece of stone or 20" .)