What is a tax ID number? It's a unique nine-digit number issued by the Social Security Administration or the IRS to anyone ...

A tax identification number (TIN) is a unique nine-digit number issued by the Social Security Administration or the Internal Revenue Service to anyone who pays taxes (personal or business). Your TIN ...

Companies, like people, are usually known by their names, but people and companies both have other types of identification, often issued by government agencies in the form of identification numbers.

Every Facebook user has a unique ID number. This number gives you some information on approximately -- but not precisely -- when you and your friends joined Facebook relative to each other. A lower ...