Piece provided, worn pipe (8)
I believe the answer is:
manifold
'pipe' is the definition.
(I know that manifold is a type of pipe)
'piece provided worn' is the wordplay.
'piece' becomes 'man' (man can mean a chess piece).
'provided' becomes 'if' (eg 'provided it's sunny' means 'if it's sunny').
'worn' becomes 'old' (associated in meaning).
'man'+'if'+'old'='MANIFOLD'
(Other definitions for manifold that I've seen before include "Various; engine part" , "Having many forms" , "performing several functions" , "car part?" , "with several features" .)