Regularly recognise Times (4)
I believe the answer is:
eons
'times' is the definition.
(eon is a kind of time)
'regularly recognise' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'recognise' are 'EONS'.
(Other definitions for eons that I've seen before include "Endless periods" , "Very long periods (US)" , "Times" , "Vast ages" , "Divisions of geological time" .)