Cutoff point (3)
(Other definitions for cap that I've seen before include "Soft headgear" , "Outdo; brimless hat" , "Headgear item" , "Better; hat" , "Dental work" .)
'cutoff point' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for end that I've seen before include "Concluding purpose" , "Butt" , "Extreme" , "Closure" , "Exterminate - object" .)