Up to the point that (3)
(Another definition for til that I've seen is " Sesame".)
'up to the point that' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for until that I've seen before include "As late as" , "Up to (a point in time)" , "As far as" , "Up to that moment" , "Unlit (anag.)" .)