periodic
periodical
annual
biannual
biennial
bimonthly
biweekly
catamenial
centenary
centennial
daily
decennial
diurnal
fortnightly
half-yearly
hebdomadal
hourly
menstrual
momentary
momently
monthly
quarterly
quotidian
secular
semestral
semimonthly
semiweekly
semiyearly
tertian
triennial
weekly
yearly