System of Record (SOR)
The authoritative system or location designated as holding the official record copy of a given type of information, so other copies can be treated as convenience copies.
A system of record (SOR) is the system or location formally designated as holding the official, authoritative copy of a given type of information. Once an SOR is defined, duplicates of that information held elsewhere can be treated as non-records (convenience copies), which keeps the organization from managing — or trying to retain — many redundant copies.
Designating systems of record is a practical necessity in modern environments where the same information is scattered across email, shared drives, and applications. It answers the question “which copy is the record?” — clarifying where retention, holds, and disposition should be applied, and reducing ROT. (The term is related to but broader than the Privacy Act’s “system of records,” which specifically means a group of agency records about individuals retrievable by a personal identifier.)