What is bounded context?

From DDD website:
[[Bounded Context]] The delimited applicability of a particular model. BOUNDING CONTEXTS gives team members a clear and shared understanding of what has to be consistent and what can develop independently.
http://dddcommunity.org/resources/ddd_terms/

From Martin Folwer:
Bounded Context is a central pattern in Domain-Driven Design. It is the focus of DDD's strategic design section which is all about dealing with large models and teams. DDD deals with large models by dividing them into different Bounded Contexts and being explicit about their interrelationships.
http://martinfowler.com/bliki/BoundedContext.html

From MSDN
The term bounded context comes from Eric Evans' book. In brief, Evans introduces this concept as a way to decompose a large, complex system into more manageable pieces; a large system is composed of multiple bounded contexts. Each bounded context is the context for its own self-contained domain model, and has its own ubiquitous language. You can also view a bounded context as an autonomous business component defining clear consistency boundaries: one bounded context typically communicates with another bounded context by raising events.
https://msdn.microsoft.com/en-us/library/jj591575.aspx

From "DDD: The Bounded Context Explained"
http://www.sapiensworks.com/blog/post/2012/04/17/DDD-The-Bounded-Context-Explained.aspx

really Explained?

Same question at
http://programmers.stackexchange.com/questions/237513/what-in-reference-to-ddd-is-a-bounded-context

Conclusion:  bounded context is a fence.

How come a key concept in DDD is with so many ambiguous definitions?
:)