Hukou refers to an individual's registration within the huji system, which is a household registration system used in mainland China. While often referred to as hukou, the formal name for the system itself is huji. The origins of this registration system date back to ancient China.
A hukou record officially identifies an individual as a permanent resident of a specific area and contains identifying information such as their name, parents, spouse, and date of birth. Because household registers are issued per family, the term hukou can also refer to a family register that documents significant life events for all members, including births, deaths, marriages, divorces, and moves.