taxpayer identification number


Tax Identification Number

A number the IRS assigns to businesses and other entities, such as trusts, for tax purposes. While the TIN exists for a variety of reasons, its main function is to ensure that each organization is billed for its own taxes, and not those of another entity with the same name. Social Security numbers serve as TINs for individuals.

taxpayer identification number (TIN)

For an individual, his or her Social Security number. For a business or fiduciary, its Employer Identification Number.