Hard-to-imagine interval (3)
I believe the answer is:
eon
(Other definitions for eon that I've seen before include "Huge time period" , "Vast age (alt. sp.)" , "Era" , "thousand million years" , "Long period of time" .)
I believe the answer is:
eon
(Other definitions for eon that I've seen before include "Huge time period" , "Vast age (alt. sp.)" , "Era" , "thousand million years" , "Long period of time" .)