The word 行业 is formed by combining two characters, each contributing a layer of meaning to create a modern concept. The first character, 行 (háng), originally depicted a crossroads and carries connotations of a row, a series, or a profession one moves through. The second, 业 (yè), historically represented a wooden frame holding musical stones or tablets, evolving to mean work, enterprise, or a lasting vocation. Together, they conceptually merge the idea of a defined path or profession (行) with the substance of work and enterprise (业) to signify a specific trade, field of business, or industry, a collective domain of professional activity.