Covered with slabs (5)
I believe the answer is:
tiled
'covered' is the definition.
(similar in meaning)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for tiled that I've seen before include "Covered eg as walls of shower area" , "covered bathroom wall?" , "Covered the roof" , "Covered or floored with baked clay" , "Covered in pottery slabs" .)