Periods longer than eras (4)
I believe the answer is:
eons
(Other definitions for eons that I've seen before include "Very long periods (US)" , "Vast ages" , "Years and years" , "Endless periods" , "Divisions of geological time" .)
I believe the answer is:
eons
(Other definitions for eons that I've seen before include "Very long periods (US)" , "Vast ages" , "Years and years" , "Endless periods" , "Divisions of geological time" .)