Definition of "periodicity"

periodicity

noun
countable and uncountable, plural periodicities
1. Recurrence of a woman's periods; menstruation.
2. The quality of being periodic; tendency to recur at regular intervals.
  Quotations
  The implications of this association of women and the moon would suggest that women were the first observers of the basic periodicity of nature, the periodicity upon which all later scientific observations were made.
  1981, William Irwin Thompson, The Time Falling Bodies Take to Light: Mythology, Sexuality and the Origins of Culture, London: Rider/Hutchinson & Co., page 97
3. (mathematics) The quality of a function with a repeated set of values at regular intervals.