Oldest university in the USA (7)
I believe the answer is:
harvard
'oldest university in the usa' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for harvard that I've seen before include "US Ivy League university" , "Member of the 11 at Cambridge, Massachusetts" , "place of learning" , "American university" , "Ivy league university in Cambridge, Massachusetts" .)