Social Security Number (SSN) A federal taxpayer identification number for Americans. An SSN number is required to get a job and claim taxes or other tax benefits. Investopedia Says: There are a lot of issues surrounding Social Security numbers and numbering in general. Many people feel that the identification of citizens in this manner is the beginning of a "Big Brother" government. However, it doesn't change the fact that you usually need an SSN to work. Related Terms: Filing Status Identity Theft Income Tax Social Security Administration - SSA Taxes |