A batch job is a job that is submitted to a non-interactive environment for execution. A batch job can be a job that includes thousands of transactions, for example in a weekly invoice procedure, but it can also be a job that only contains one main transaction such as an order confirmation.
A batch job can be initiated from the job scheduler (or more correct, the job scheduler initiates a program which starts a batch job) or by another transaction. A batch job can also be a part of a mainly interactive job, where the interactive part submits the batch part with specific settings attached to it. The batch job performs in that way as an extension of the interactive environment, to obtain better performance in the time-critical operations.
Many jobs that update M3 BE, and especially those creating output from M3 BE, are submitted. This submitted job is in control of the business transaction after submission.
The batch environment is thus an essential part of M3 BE, and this environment must be up and running to get most business processes to function properly.