There were days of it in historical times (3)
I believe the answer is:
old
'historical times' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'there were days of it' is the wordplay.
I cannot really see how this works, but
'days' could be 'd' (abbreviation for days) and 'd' is found in the answer.
'of' could be 'o' and 'o' is found within the answer.
A single letter 'l' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for old that I've seen before include "Long-lived" , "SECOND PART OF 14" , "Obsolete" , "Senescent" , "Stale" .)