noun.
Periodic character; habitual tendency or disposition to recur at stated intervals of time.
noun.
In physical, the number of recurrences of a periodic motion, such as a vibration, in a unit of time; specifically, in electricity, the number of complete periods or cycles per second of an alternating or oscillating current: same as frequency. The usual electrical frequencies are 25 and 60 in the United States and 50 in Europe.
noun.
In botany, the habit in a plant of adjusting its growth or the movements of its organs to regular changes in conditions (of light, heat, etc.), either annual or diurnal. Periodicity is also exhibited in some spontaneous movements not correlated with time of day or season. See phenology, sleep, 5, sensitive-plant, and periodic movement.