Old Greek university plugging dissertations (7)
I believe the answer is:
theseus
'old greek' is the definition.
'theseus' can be an answer for 'greek' (I have seen 'ancient Greek' mean 'theseus' so perhaps 'greek' could also mean 'theseus'). I am not certain of the 'old' bit.
'university plugging dissertations' is the wordplay.
'university' becomes 'U' (abbreviation for university).
'plugging' means one lot of letters goes inside another (inserted letters plug up a gap in the word).
'dissertations' becomes 'theses' ('thesis' can be a synonym of 'dissertation').
'u' inserted into 'theses' is 'THESEUS'.
Can you help me to learn more?
(Other definitions for theseus that I've seen before include "Greek king" , "Heroic figure" , "Duke in A Midsummer Night's Dream" , "Heroic Greek" , "Occasion when public may visit (eg, school)" .)