An identification number, also known as an ID or identity number, is a unique numerical code assigned to identify individuals or objects. This number can be used for various purposes such as verifying someone's identity, tracking their movements, or accessing their personal information. Identification numbers are commonly used in many different contexts including governmental and non-governmental organizations, financial institutions, healthcare systems, educational institutions, and businesses among others. Some common examples of identification numbers include social security numbers, national ID cards, driver's license numbers, passport numbers, student IDs, and employee badge numbers.