Point in dissertation or theorem (5)
I believe the answer is:
north
'point' is the definition.
(I know that north is a type of cardinal compass point)
'in dissertation or theorem' is the wordplay.
'in' says the answer is hidden in the clue.
'NORTH' can be found hidden inside 'dissertation or theorem'.
(Other definitions for north that I've seen before include "Top of most maps" , "Pole" , "who has to follow West's lead?" , "Lord -, PM; bearing" , "Compass point at 0 or 360 degrees" .)