| Term: | Persistent Identifier (PID) |
| Definition: |
An Internet-based identifier, such as a URL, that is meant to be valid for long term reference. Persistence of an identifier is purely a matter of service and is neither inherent in an object nor conferred on it by a particular naming syntax. |
| Examples: |
Well-known kinds of PID that can be expressed as URLs include ARK (Archival Resource Key), DOI (Digital Object Identifier), Handle, PURL (Persistent URL), and URN (Uniform Resource Name). |