periodicity

Recurrence of a woman's periods; menstruation.

The quality of being periodic; tendency to recur at regular intervals.

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.

A recent wavelet analysis of the turbidity data showed clear periodicities of turbidity in the three Pilbara datasets during both the baseline and dredge phases of the studies (Stark, unublished data) peaking semidiurnally associated with tides, diurnally associated with daily sea breezes and sometimes fortnightly associated with spring-neap cycles.

The quality of a function with a repeated set of values at regular intervals.