means The quality of happening at consistent, predictable intervals or following a steady, uniform pattern.

from From Latin 'regularis,' meaning 'according to rule,' built on 'regula,' a straight stick or ruler — the carpenter's tool for keeping lines true. 'Regula' itself traces back to 'regere,' to guide or rule straight, the same root that gives us 'rule,' 'regal,' and 'rectangle.' So at its heart, regularity is the idea of measuring the world against a straightedge and finding it lines up.