Academy (7)
(Other definitions for college that I've seen before include "University establishment" , "prison" , "pudding?" , "Place of higher education" , "eg Eton" .)
'academy' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for institute that I've seen before include "Set in motion, establish" , "Educational organisation, found or begin one" , "Organisation for promotion of scientific or educational activity" , "Establish - seat of learning" , "Begin (legal proceedings)" .)
(Other definitions for khan that I've seen before include "Imran --, cricketer" , "Central Asian prince or chief" , "Persian governor" , "Eastern emperor" , "Asian title for a prince" .)