PowerShell cmdlet that runs a script containing statements from the languages (Transact-SQL and XQuery) and commands supported by the SQL Server sqlcmd utility.
For MicroSoft's official documentation on this cmdlet see: https://msdn.microsoft.com/en-GB/library/cc281720.aspx
Alternative options to this command exist. For a discussion of these see: https://dba.stackexchange.com/questions/17435/which-powershell-technique-should-i-use-to-talk-to-sql-server