“Gong” (“共”) is an associative character that looks like two hands holding a square article in the oracle bone script. The shape changes slightly in the small seal script and is simplified to its current form in the regular script. From the shape of “gong”, we can see that the original meaning of this character is “to present something with both hands”, and “to supply or provide”. The character also took on the meaning of “common, mutual” in the evolving process, and the sense of “to supply or provide” is transferred to another character “供” (also pronounced as “gong”) with an additional person (“亻”)radical. Thus, the character “共” is in most cases used to mean “common”, “shared” and “together” etc.
