SSN or Social Security Number is an identification number assigned to U.S. citizens and residents. It is a crucial piece of information used for various purposes, including tax and credit records. However, in some cases, individuals may prefer using other terms to refer to their SSN. "Social Security ID" is a commonly used synonym for SSN. Other alternatives include "Social Security Card Number," "National Identification Number," "Taxpayer Identification Number," and "Federal Taxpayer Identification Number." While these terms are somewhat interchangeable, they all refer to the same unique identifier used by the U.S. government to track individual benefits and taxes.