Range offered by school and university over time (5)
I believe the answer is:
gamut
'range' is the definition.
(gamut is a kind of range)
'school and university over time' is the wordplay.
'school' becomes 'gam' (I've seen this in other clues).
'and' means one lot of letters go next to another.
'university' becomes 'u' (abbreviation for university).
'over' says to put letters next to each other.
'time' becomes 't' (abbreviation).
'gam'+'u'+'t'='GAMUT'
'offered by' is the link.
(Other definitions for gamut that I've seen before include "The whole range or scope of anything" , "Entire scope" , "The whole range of, say emotions" , "Complete extent or range" , "Whole range (from A to Z)" .)