An identifier which is unique amongst all identifiers used for a given set of entities.

In OCDS, the term use case has been used to refer to categories of open contracting data use - such as the use of open contracting data to support 'value for money in procurement'. In software engineering, the term 'use case' is often used to describe in detail the specific set of steps or actions a user would take to achieve a particular goal. The OCDS usage is more general, and broader, than this.