Hypernym for "day", "month", "week", "year"

I would like to know if there is a single-word hypernym for day, month, week and year.


Solution 1:

Time period is general enough:

time period n. an amount of time

Solution 2:

Their hypernym would be based in their singular aspect of similarity — into what set can they all fit. So words like time and span (or even time span) would do the trick assuming you mean a duration. If you mean a specific period then try, um, period.