Periodic; Periodical

Part of speech: adjective (a.)

1. Of or pertaining to a period or periods, or to division by periods. The periodicaltimes of all the satellites. Sir J. Herschel.

2. Performed in a period, or regular revolution; proceeding in a series of successive circuits; as, the periodical motion of the planets round the sun.

3. Happening, by revolution, at a stated time; returning regularly, after a certain period of time; acting, happening, or appearing, at fixed intervals; recurring; as, periodical epidemics. The periodic return of a plant's flowering. Henslow. To influence opinion through the periodical press. Courthope.