2. "Bei" is a first-class word in Chinese, which was first seen in Oracle Bone Inscriptions. Its original meaning is the general name of Gastropoda and Clarambranchia in oysters, clams or other mollusks, that is, Shuowen Jiezi: "Shellfish are also marine insects." Also refers to shells, shell-like patterns, etc. , also refers to ancient coins made of shells or shells.