Material with which Silas wove (5)
I believe the answer is:
sisal
'material' is the definition.
(sisal is a kind of material)
'silas wove' is the wordplay.
'wove' indicates an anagram (I've seen 'weave' mean this).
'silas' with letters rearranged gives 'SISAL'.
'with which' acts as a link.
(Other definitions for sisal that I've seen before include "Hemp fibre" , "Agave rope-fibre" , "Plant producing rope" , "Fibre of Mexican agave" , "Fibre used in rope-making" .)