Time periods (6)
'time periods' is the definition.
(era is a kind of time period)
This is all the clue.
(Other definitions for eras that I've seen before include "typeface" , "Long and distinct periods of history" , "Periods, ages" , "Epochs" , "Periods of time" .)
'time periods' is the definition.
(month is a kind of time period)
This is all the clue.
(Other definitions for months that I've seen before include "There are twelve of these" , "Divisions of time" , "17 and December" , "Calendar divisions" , "Divisions of year" .)
'time periods' is the definition.
(span is a kind of time period)
This is all the clue.