This is a really awesome intro into Context Mapping, if your getting started or even if you need a refresher.
Introduction to Context Mapping
A Bounded Context is a boundary. It has it’s own language within the boundary. There is a purpose to it, too - Reusability is not key concern. Models are specific.
It can also be seen as team first boundary (Team Topologies space).
The bounded context does not show the dynamics between contexts (nor between teams).