What is the BEST description of a proprietary database?

A proprietary database is a type of database that is owned and controlled by a specific company or organization, which restricts its use, modification, and distribution to authorized users only. This means that the underlying code and architecture are not publicly available, making it difficult for third parties to customize or integrate the database with other systems. Proprietary databases often come with licensing fees and support services, offering features tailored to the needs of the owning entity. Examples include Oracle Database and Microsoft SQL Server.