Regularity (glossary)
A uniformity or similarity that exists in multiple entities or at multiple times. (von Bertalanffy 1968).
Sources
von Bertalanffy, L. 1968. General System Theory: Foundations, Development, Applications, Revised ed. New York, NY, USA: Braziller.
Discussion
The existence of similarities and differences between systems from different domains is one of fundamental ideas behind systems thinking (see Concepts of Systems Thinking)