Cosm

A system or entity that exists on an intermediate scale between the very large and the very small, and that provides a framework for understanding the structure and interactions between different scales of systems or entities."

An octave is an example of a cosm within the field of music.

The concept of a cosm, as an intermediate-level
system or entity that exists between the very large and the very small, provides a framework for understanding the structure and interactions between different scales of systems within the universe.