Ivy League university (4)
'ivy league university' is the definition.
(Yale University)
This is the entire clue.
(Other definitions for yale that I've seen before include "New Haven university" , "Member of the 11 - type of lock" , "University man" , "Heraldic animal" , "American university or kind of lock" .)
(Other definitions for princeton that I've seen before include "American university" , "where War of Independence battle was fought?" , "College" , "Member of the 11 in New Jersey" , "US ivy league university" .)