Definition:
Whether you are working in a sales organization or a factory or an R&D lab, you are also a part of a larger system of delivering value to customers. This end-to-end system that collaborates (at least in some fashion!) to deliver value to customers is called a Value Delivery System.
The problem with such situations is that breakdowns and lack of alignment within the whole system can hinder you from optimizing the value that you create and deliver. The activity of improvement thus focuses on the whole system.
In any VDS work, an early stage is in scoping out the system on which you are going to work. It can be soup-to-nuts stuff or can be constrained within a single organization.
Further Reading:
Book: The Firm by Duff McDonald