Ceramic slab (4)
I believe the answer is:
tile
'ceramic slab' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tile that I've seen before include "Roofing material" , "Thin rectangular slab to cover surfaces" , "Roofing slab" , "Hat" , "Mah-jong piece" .)