1.the basic rhythmic unit in a piece of music;
the piece has a fast rhythm
2.recurring at regular intervals
3.an interval during which a recurring sequence of events occurs;
the neverending cycle of the seasons
4.the arrangement of spoken words alternating stressed and unstressed elements;
the rhythm of Frost's poetry
5.natural family planning in which ovulation is assumed to occur 14 days before the onset of a period (the fertile period would be assumed to extend from day 10 through day 18 of her cycle)