In Athens at the time in question (4)
I believe the answer is:
then
'time in question' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'in athens at' is the wordplay.
'in' indicates the answer is hidden within the clue.
'THEN' is hidden within 'athens at'.
'the' is the link.
Can you help me to learn more?
(Other definitions for then that I've seen before include "Once upon a time" , "Subsequently - previously" , "soon?" , "At that time; next" , "Consequently" .)