SQL Server is a relational database management system from Microsoft.
Microsoft's SQL Server is a suite of relational database management system (RDBMS) products providing multi-user database access functionality. It originated from the Sybase SQL Server 4.x codebase and Transact-SQL dialect (T-SQL), but it has forked significantly since then.
SQL Server is available in multiple versions, typically identified by release year, and versions are subdivided into editions to distinguish between product functionality.