The word "寻常" is formed through the fusion of two ancient measurement units: a "寻" was eight Chinese feet (大约八尺), and a "常" was double that, sixteen feet. These were standard, commonly used lengths for measuring cloth or distance. Over time, their concrete meaning as routine, everyday measurements evolved metaphorically into the abstract idea of something being "ordinary", "common", or "usual", as these were the standard sizes one would encounter regularly. Thus, the term originates from a tangible, quantitative standard in daily life that transformed into a qualitative description of the normal and unremarkable.