Adj. periodic, periodical; serial, recurrent, cyclical, rhythmical; recurring &c v.; intermittent, remittent; alternate, every other. hourly; diurnal, daily; quotidian, tertian, weekly; hebdomadal^, hebdomadary^; biweekly, fortnightly; bimonthly; catamenial^; monthly, menstrual; yearly, annual; biennial, triennial, &c; centennial, secular; paschal, lenten, &c regular, steady, punctual, regular as clockwork.