Microscopic scale

The microscopic scale (from Greek: μικρός, mikrós, "small" and σκοπέω, skopéō "look") is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes considered the scale between the macroscopic and the quantum regime.

https://en.wikipedia.org/wiki/Microscopic_scale