Immediate — second (7)
I believe the answer is:
instant
I believe this is a double definition.
'immediate' is the first definition.
(I've seen this before)
'second' is the second definition.
(I know this)
(Other definitions for instant that I've seen before include "Precise moment" , "Fast, flash" , "Sudden; moment" , "Occurring immediately, like some fast food" , "Immediate, twinkling" .)