Hugely long time (3)
I believe the answer is:
eon
(Other definitions for eon that I've seen before include "An immense time" , "Geological period" , "billion years" , "Very long period (US and technical spelling)" , "Very long age" .)
I believe the answer is:
eon
(Other definitions for eon that I've seen before include "An immense time" , "Geological period" , "billion years" , "Very long period (US and technical spelling)" , "Very long age" .)