Definitions for "Value stream"
All activities, both value added and nonvalue added, required to bring a product from raw material state into the hands of the customer, bring a customer requirement from order to delivery and bring a design from concept to launch.
A value stream is a series of all actions required to fulfill a customer's request, both value added and not.  A value stream contains a product or a family of products that have similar material and information flows.  Value Streams are typically identified using a combination of Pareto Analysis and Process Routing analysis.
a series of processes or events that result in a product a customer is willing to purchase