Periodicity (noun)

1. The property of recurring regularly at fixed intervals or with a fixed pattern.
2. The characteristic of repeating regularly in time, space, or some other aspect.

Origin:

From latin periodicus, from periodeia 'recurrence', from greek periodeia, from periodos 'a circuit, a return'.

Examples:

1. The periodicity of the tides is well known, as they rise and fall with the moon's gravitational pull.
2. The periodicity of the economic cycle is studied by economists in order to make predictions and plan for the future.
3. The periodicity of the planets in their orbits can be described by mathematical models.
4. The periodicity of the human heartbeat is carefully monitored by medical professionals in order to detect any irregularities.
5. The periodicity of the sound waves was important in the development of Fourier analysis in mathematics and physics.