Software Architect's Handbook

Separating the domain into subdomains

One practice of DDD is to separate the domain model into multiple subdomains. While a domain is the entire problem space that the software solution is being developed for, a subdomain is a partitioned piece of the overall domain. This is particularly useful for large domains, where it is not feasible to have one large and unwieldy domain model.

By focusing on one subdomain at a time, it reduces complexity and makes the overall work more digestible. Rather than attempting to address too many issues at once, dividing your domain into subdomains provides more of a divide and conquer approach.

For example, in a student information system, you may have subdomains for contact management, admissions, financial ...