Historic period (3)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
era
'historic period' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for era that I've seen before include "Special time" , "Are involved in time span" , "Important time" , "Geological period" , "8" .)