Study Hesiod's conclusion in French (3)
I believe the answer is:
den
'study' is the definition.
(den can mean an office or study)
'hesiod's conclusion in french' is the wordplay.
'conclusion' says to take the final letters.
'in french' becomes 'en' ('in' in French).
The last 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" .)