Sculpt a slab of wood (5)
I believe the answer is:
balsa
'wood' is the definition.
(type of wood)
'sculpt a slab' is the wordplay.
'sculpt' indicates anagramming the letters.
'a'+'slab'='aslab'
'aslab' with letters rearranged gives 'BALSA'.
'of' is the link.
(Other definitions for balsa that I've seen before include "Very light wood in a slab" , "Wood used in model making" , "Lightweight timber" , "Strong lightweight wood" , "Wood used by model makers" .)