Yesteryear (4)

I believe the answer is:
yore
'yesteryear' is the definition.
(I know that yore is a type of yesteryear)
This is all the clue.
(Other definitions for yore that I've seen before include "Long ago (literary)" , "Formerly, of long ago" , "Time long ago" , "Old usage for formerly, as in days of. . ." , "Long ago (poetic)" .)