Countless lifetimes (3)
I believe the answer is:
eon
(Other definitions for eon that I've seen before include "Vast age (alt. sp.)" , "Vast period" , "thousand million years" , "Prolonged period" , "Major division of geological time" .)
I believe the answer is:
eon
(Other definitions for eon that I've seen before include "Vast age (alt. sp.)" , "Vast period" , "thousand million years" , "Prolonged period" , "Major division of geological time" .)