Microsoft SQL Server is a relational database management system (RDBMS) developed by Microsoft. It is widely used for storing and retrieving data as requested by other software applications. SQL Server supports a variety of transaction processing, business intelligence, and analytics applications in corporate IT environments. It offers features such as data integration, reporting, analysis, and security. SQL Server is scalable, supporting small to large-scale enterprise applications, and it integrates well with other Microsoft products and services, making it a robust choice for managing and querying relational data.