Origin

This character pictures a simple measuring container used in everyday life. The box-like shape with an opening at the top represents a wooden measuring vessel, the kind used to portion out grain or other dry goods. In ancient China and Japan, a standard measure called a shō was exactly this size—about 1.8 liters. The shape is so straightforward that it directly shows what the word means: a tool for measuring, and by extension, the specific volume it holds.