Persistent object identifier
In database design, a persistent object identifier (POID) is a unique identifier of a record on a table, used as the primary key. Important characteristics of a POID are that it does not carry business information and are not generally exported or otherwise made visible to data users; as such a POID has many of the characteristics of a surrogate key.
Source: Wikipedia — Persistent object identifier (CC BY-SA 4.0)