What is another word for identification number?
Pronunciation: [a͡ɪdˈɛntɪfɪkˈe͡ɪʃən nˈʌmbə] (IPA) 
An identification number is a unique set of digits or characters assigned to individuals, companies, or products by an organization for identification and tracking purposes. There are various synonyms used for identification numbers such as ID number, unique identifier, registration number, security code, customer number, code, PIN, reference number, serial number, social security number, tracking number, tax ID, and many more. These synonyms may differ based on the specific purpose of the identification number and the industry it is used in. Nonetheless, they all serve the same purpose of distinguishing one entity from another and ensuring their identification and management.
