an interval during which a recurring sequence of events occurs

a periodically repeated sequence of events

a series of poems or songs on the same theme

a single complete execution of a periodically repeated phenomenon

the unit of frequency; one hertz has a periodic interval of one second (named for Heinrich Rudolph Hertz)

to go through a complete series of events or stages in a cyclical or repetitive manner

to cause or facilitate the movement or progression of something through a recurring sequence

to move or progress in a pattern or sequence of events that repeats itself regularly