Regularity (noun)

1. The quality or state of being regular in shape, arrangement, or occurrence.
2. The quality or state of being systematic or conforming to a pattern.

Origin:

Late 16th century, from latin regularitas, from regula, meaning "rule".

Examples:

1. The regularity of his sleep patterns is a sign of good health.
2. The regularity of the waves was a sure sign that the wind was picking up.
3. The regularity of the company's profits is a testament to its efficient management.
4. The regularity of the planetary orbits is an amazing phenomenon.
5. The regularity of the assembly line made it possible to produce cars in large numbers.