DDD: What is the scope of the ubiquitous language? Is it domain or bounded context?

Question

One key concept in Domain-Driven Design (DDD) is the ubiquitous language.

What is the typical scope (consistency border) of such a ubiquitous language? Is it scoped by the bounded context (e.g. a system/component in a certain domain) or by the domain itself? In bigger enterprises, different systems (i.e. bounded contexts) might implement the same domain.

My assumption is that it's bound to a bounded context as consistency cannot be guaranteed across multiple bounded context (even if they belong to the same domain) but I am not sure.

Answer 1

Bounded Context is where Ubiquitous Language lives.

Vaughn Vernon defines DDD in short as:

Developing Ubiquitous Language within Bounded Context

This question has been asked and answered before

UPDATE: I gave a talk at DDD Norway meetup about, covering the importance of UL and contexts. Slides can be found here.

Answer 2

The ubiquitous language is defined within a bounded context. This becomes obvious when you look at different BCs that contain the same term. The concept of a book in an online shop is completely different than a book in a authoring system.

From Implementing DDD by Vaughn Vernon:

Bounded Context Is Explicit and Linguistic

A Bounded Context is an explicit boundary within which a domain model exists. Inside the boundary all terms and phrases of the Ubiquitous Language have specific meaning, and the model reflects the Language with exactness.