A SQL Server Job is a task that can be executed by the SQL Server Agent
SQL Server allows the creation of individual jobs, repeatable processes which can be run on-demand or via a preset schedule.
Each job consists of one or more job steps, which are executed in sequence. A job step can be one of the following:
Executable programs and operating system commands.
Transact-SQL statements, including stored procedures and extended stored procedures.
PowerShell scripts.
Microsoft ActiveX scripts.
Replication tasks.
Analysis Services tasks.
Integration Services packages.
SQL Server jobs are operated through the SQL Server Agent. Frequent uses include database maintenance tasks, ETL package execution, cube processing, and script execution.