Data Universal Numbering System
The Data Universal Numbering System, abbreviated as DUNS or D-U-N-S, is a proprietary system developed and managed by Dun & Bradstreet (D&B) that assigns a unique numeric identifier, referred to as a "DUNS number" to a single business entity. It was introduced in 1963 to support D&B's credit reporting practice.
Source: Wikipedia — Data Universal Numbering System (CC BY-SA 4.0)