A Taxpayer Identification Number (TIN) is a unique identifier assigned to individuals and businesses for tax purposes. It is used by the Internal Revenue Service (IRS) in the United States to track tax obligations and ensure accurate reporting of income. TINs can take various forms, including Social Security Numbers (SSNs) for individuals and Employer Identification Numbers (EINs) for businesses. Having a TIN is essential for filing tax returns, opening bank accounts, and applying for loans. It helps streamline the tax process and prevents identity theft by ensuring that each taxpayer is uniquely identified. Proper use of a TIN is crucial for compliance with tax laws.