Philosopher's works (4)
I believe the answer is:
mill
I believe this clue is a double definition.
'philosopher's' is the first definition.
(thesaurus)
'works' is the second definition.
(mill is a kind of works)
(Other definitions for mill that I've seen before include "Vacuous" , "J.S. - - , philosopher" , "Flour is produced here" , "Flour factory" , "Place for grinding flour" .)