Recount's every second time (3)
I believe the answer is:
eon
'time' is the definition.
(I know that eon is a type of geologic time)
'recount's every second' is the wordplay.
'every second' means one should take alternating letters (I've seen 'every second of' mean this).
The alternate letters of 'recount' are 'EON'.
(Other definitions for eon that I've seen before include "Immense period" , "Vast period" , "An immense time" , "Age, epoch" , "Prolonged period" .)