A number stating that your treatment has been approved by your insurance plan. Also called a Certification Number or Prior-Authorization Number.

The number assigned by MERX to a purchase by credit card.

The number assigned to the customer by Microsoft after initiating an Open License account. This number allows for reorders at the same discount level for two years.

Number assigned by OCLC to authorize use of OCLC services. Usually used in conjunction with a password. See also password, default system, default holding library code.

The unique number assigned by the PAK issuer to a specific PAK. The PAK issuer name and authorization number identify a license.