Licence for each US college (6)
I believe the answer is:
permit
'licence' is the definition.
(I know that licence can be written as permit)
'each us college' is the wordplay.
'each' becomes 'per' ('per' can mean for each).
'us college' becomes 'MIT' (I've seen this in other clues).
'per'+'mit'='PERMIT'
'for' acts as a link.
(Other definitions for permit that I've seen before include "Official document giving authorisation" , "Let - pass" , "Licence -- license" , "Let; enabling document" , "Allow - visa" .)