Social Security - A term used to describe an agency, a card and two types of tax. The card contains a unique nine digit identification number issued to qualified individuals primarily to determine eligibility for social benefits through various forms of employment. The number on the card is also used for tax recordkeeping. A treaty can give certain tax benefits. A note of caution, however.
Tax treaties are very specific.
Just because someone is a resident of a tax treaty country does not mean that the person will automatically qualify for tax benefits. An individual may not be eligible for a Social Security number, which is routinely issued only to U.S. citizens, U.S. permanent residents and nonimmigrants with legal work permission. In that case, the nonimmigrant must apply to the IRS for a unique nine digit code for tax-related purposes. Withholding is the term used to describe a portion of your check amount that an employer is required to pay directly to federal, state, and city taxation authorities in anticipation of your annual income tax obligations. The check you receive, therefore, is for less than you earned during the pay period.