Oracle BPM's Multi-instance Subprocess is a type of a subprocess activity that can take an array of items as input and then handle each individual item in the array separately. The number of times the subprocess is executed can be determined at runtime by the size of the array at runtime. Each work item that is spawned is then acted on individually.
A typical use case for this is when you have an order with many order items inside of it. If each inidivdual order item needs some kind of approval or handling, consider doing this using Oracle BPM's BPMN based Multi-instance Subprocess activity.
The video below takes you through step-by-step instructions on how to create and test this common process design pattern using either Oracle BPM 11g or 12c.