A concept does not need one meaning everywhere in a business. Purposeful semantics defines what a concept means for a particular purpose, then leaves out rules and responsibilities that do not serve that purpose. This creates a deliberate semantic boundary rather than letting everything associated with a familiar term accumulate in one subdomain. section 9.3.2
A customer is not one responsibility
A single Customer subdomain could gather profiles, order history, payment details, shipping preferences, and loyalty. That breadth risks tight coupling. For a purpose such as showing order history, define “customer” by the value it provides to that purpose; do not automatically bring the other concerns into the same definition. section 9.3.2
Start with a purpose, work backward to the concept’s relevant value, and remove unrelated meaning. Revisit the boundary as business language changes: a term that meant one thing a few years ago may need a different definition now. section 9.3.2
