National identification number
A national identification number or national identity number is used by the governments of many countries as a means of uniquely identifying their citizens or residents for the purposes of work, taxation, government benefits, health care, banking and other governmentally-related functions. They allow authorities to use a unique identifier which can be linked to a database, reducing the risk of misidentification of a person.
Source: Wikipedia — National identification number (CC BY-SA 4.0)