"Length scale" refers to the size or distance over which something occurs or is measured. It helps us understand the magnitude or extent of an object or phenomenon. Full definition
Unfortunately, it is very difficult to measure these kind of movements because they occur on a very small length scale. (sciencedaily.com)
At smaller size and length scales in nature, however, such as those involving atoms and photons and their behaviors, classical physics falls short. (sciencedaily.com)
A very short (14 item) version of the scale was found to have comparable properties to the full length scale. (cambridge.org)