Which letter is used twice in academic submission? (6)
I believe the answer is:
thesis
'academic submission?' is the definition.
(a thesis is a piece of academic work)
'which letter is used twice' is the wordplay.
I cannot quite understand how this works, but
'letter' could be 'he' (he is a kind of letter) and 'he' is present in the answer.
'is' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'in' is the link.
Can you help me to learn more?
(Other definitions for thesis that I've seen before include "Dissertation - idea" , "He sits (anag) - treatise" , "Researched dissertation" , "Article by son is in paper" , "Academic dissertation" .)