An identification number is a unique combination of numbers or letters that is used to distinguish and identify something or someone. It is like a special code assigned to a specific item or person to help keep track of them. Full definition
Additional information is collected on property transfer tax returns, including tax identification numbers for individuals using bare trusts. (recbc.ca)
An acronym for personal identification number which is a set of digits that are used to verify a cardholder or authorized user's identity at the point of sale. (creditcardeducation.com)
Only 650 copies are available, and each one has a unique identification number on a badge stuck to the center console. (automobilemag.com)