Microsoft SQL Server 2005/2008 refers to specific versions of the Microsoft SQL Server relational database management system released by Microsoft. SQL Server 2005 introduced significant features such as database mirroring, snapshot isolation, and native XML support, while SQL Server 2008 introduced features such as transparent data encryption, policy-based management, and spatial data types. SQL Server 2005/2008 is used for storing, retrieving, and managing structured data in enterprise applications and data warehousing solutions.