The word "古代" is formed by combining two independent characters, each contributing a core meaning to create a new, unified concept. The first character, "古", pictographically represents something old or ancient, often interpreted as ten mouths (十口) passing down stories through generations, thus solidifying its meaning of antiquity. It is joined with "代", which signifies an era, generation, or period of time. When placed together, they do not modify each other grammatically but rather merge their inherent ideas; the "ancient" ("古") fuses directly with "era" ("代") to conceptually form "ancient times" or "antiquity" as a single, complete notion.