Hyperbolic wait time
I believe the answer is:
eon
'hyperbolic wait time' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eon that I've seen before include "Vast age (alt. sp.)" , "plenty of time" , "An immense time" , "billion years" , "Very long period (US and technical spelling)" .)