The word 公共 is formed through the combination of two synonymous characters, 公 and 共, both of which independently convey the core idea of "commonality" or "shared by all". 公 carries meanings of public, communal, and impartial, while 共 means shared, joint, or together. By pairing them, the word creates a reinforced and more comprehensive concept of "public", where the collective, shared nature of something, be it space, property, or interest, is emphasized through this harmonious semantic duplication.