Don't limit Domain to nouns
Don’t limit your Core Domain to nouns alone. Rather, consider expressing your Core Domain as a set of concrete scenarios about what the domain model is supposed to do. When I say “scenarios” I don’t mean use cases or user stories, such as is common in software projects. I literally mean scenarios in terms of how the domain model should work—what the various components do. This can be accomplished in the most thorough way only by collaborating as a team of both Domain Experts and developers. Here’s an example of a scenario that fits with the Ubiquitous Language of Scrum:
The product owner commits a backlog item to a sprint. The backlog item may be committed only if it is already scheduled for release, and if a quorum of team members have approved commitment. If it is already committed to a different sprint, it must be uncommitted first. When the commitment completes, notify the sprint from which it was uncommitted and the sprint to which it is now committed.