# What Is a Subdomain? > [!Note] > A **subdomain** partitions the global business domain into logical areas, each governed by its own **domain model**, led by **specific [[Domain Expert]]**, articulated in a **[[Ubiquitous Language]]**, bound by coherent **business rules**, and framed within **clear conceptual boundaries**. A subdomain represents a focused segment of the broader business sphere, encapsulating a cohesive set of concepts and rules. By assigning dedicated **[[Domain Expert]]'s'** to each subdomain, the team ensures deep knowledge and precise decision-making. Every subdomain communicates in its tailored **[[Ubiquitous Language]]**, which unifies technical and business terminology to avoid misunderstandings. The **domain model** within a subdomain captures its unique responsibilities and behaviors, while a well-defined collection of **business rules** enforces consistency. Finally, establishing **clear conceptual boundaries** prevents overlap with neighboring subdomains, preserving autonomy and allowing each area to evolve independently. --- ## References - Vernon, V. (2016). _Domain-driven design distilled_. Addison-Wesley Professional. - Vernon, V. (2013). _Implementing domain-driven design_. Addison-Wesley Professional. - Khononov, V. (2021). _Learning domain-driven design: Aligning software architecture and business strategy_. O’Reilly Media. - Alammar, J., & Grootendorst, M. (2024). _Hands-on large language models: Language understanding and generation_. O’Reilly Media. - Evans, E. (2003). _Domain-driven design: Tackling complexity in the heart of software_. Addison-Wesley Professional. - Millett, S., & Tune, N. (2015). _Patterns, principles, and practices of domain-driven design._ Wrox.