There is some grey area between workflow and BPM. Workflow is a somewhat more technical description (orchestration is a very technical term that tends to be used in this context also). BPM is more of a category focused on Business Processes. Thus you could even say that Workflow is one way to implement Business Processes, and that BPM is about the management of workflow. So you are right in suggesting that BPM is like workflow with a manager interface -- it is literally the management of business processes, which can be in some cases manifested as workflow.
This was first published in October 2005