Definition of business process

What do people mean by "business process",
in the context of "business process model"?

1. Sending and receiving a business document,
    e.g. a purchase order.
2.  Purchasing something, including a series 
     of messages in a structured conversation,
     e.g. PO, acknowledgement, shipping notice,
     receipt, invoice, payment, return, etc.
3.  The workings of an internal business department, 
     like the Procurement Process.
4.  All activities involved in satisfying a customer order,
     e.g. an instance of a multi-company supply chain.
5.  Something else...

I have seen all of the above definitions in recent
ecommerce articles.  Just wondering which one(s)
will be used in ebXML?

P.S. I have tried to ask this question before in the
Requirements group and on the recent BP conference
call, but I think the answer changed in Orlando, and
I was too inarticulate to ask the question clearly
over the phone.

Thanks,
Bob Haugen
Logistical Software LLC