National Insurance number
The National Insurance number is a number used in the United Kingdom in the administration of the National Insurance or social security system. It is also used for some purposes in the UK tax system. The number is described by the United Kingdom government as a "personal account number".
Social Security (United States)
In the United States, Social Security is the commonly used term for the federal Old-Age, Survivors, and Disability Insurance (OASDI) program and is administered by the Social Security Administration. The original Social Security Act was signed into law by President Franklin Roosevelt in 1935, and the current version of the Act, as amended, encompasses several social welfare and social insurance programs.