Study Hesiod's conclusion in French (3)
I believe the answer is:
den
'study' is the definition.
(term for a study or office)
'hesiod's conclusion in french' is the wordplay.
'conclusion' indicates one should take the final letters.
'in french' becomes 'en' ('in' in French).
The final letter of 'hesiod' is 'd'.
'd'+'en'='DEN'
(Other definitions for den that I've seen before include "Miserable place" , "Room for work or play" , "Animal's lair or man's study" , "Hideaway" , "Hiding place" .)