Type of lock (4)
'type of lock' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for yale that I've seen before include "US university; lock" , "American university or kind of lock" , "Famous American university in Connecticut" , "Member of the 11 - type of lock" , "University; lock type" .)
(Other definitions for caps that I've seen before include "Bottle tops" , "Imposes limits on" , "Style of GBS writing" , "Coverings for heads or bottles" , "Headgear for international players" .)