Area in good order round university's central hall (6)
I believe the answer is:
atrium
'central hall' is the definition.
(I've seen this before)
'area in good order round university's' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'in good order' becomes 'trim' (I've seen this before).
'round' indicates putting letters inside.
'university' becomes 'u'.
'trim' enclosing 'u' is 'trium'.
'a'+'trium'='ATRIUM'
(Other definitions for atrium that I've seen before include "Church vestibule" , "Roman courtyard" , "Central court/hall" , "Central courtyard" , "Central chamber in an ancient Roman house" .)