noun (n)

• the basic rhythmic unit in a piece of music(noun.communication)

  Example:
  The piece has a fast rhythm.
  

  Synonym:
  beat, musical rhythm
  

  source: wordnet30
• recurring at regular intervals(noun.attribute)

  Synonym:
  regular recurrence
  

  source: wordnet30
• an interval during which a recurring sequence of events occurs(noun.time)

  Synonym:
  cycle, round
  

  source: wordnet30
• the arrangement of spoken words alternating stressed and unstressed elements(noun.communication)

  Example:
  The rhythm of Frost's poetry.
  

  Synonym:
  speech rhythm
  

  source: wordnet30
• 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)(noun.act)

  Synonym:
  calendar method, calendar method of birth control, rhythm method, rhythm method of birth control
  

  source: wordnet30
• In the widest sense, a dividing into short portions by a regular succession of motions, impulses, sounds, accents, etc., producing an agreeable effect, as in music poetry, the dance, or the like.(noun)

  source: webster1913