Layered Architecture organizes code into distinct layers (Presentation, Business, Data Access) with clear dependency rules, ensuring that each layer has a specific responsibility and only depends on lower layers [citation:2].
Layered Architecture is one of the most traditional structural patterns, dividing an application into horizontal layers based on responsibility. The classic three layers are the Presentation layer (UI), the Business layer (domain logic), and the Data Access layer (persistence and I/O). The key principle is the Dependency Rule: dependencies can only point inward, meaning the Presentation layer can depend on the Business layer, but the Business layer cannot depend on the Presentation layer. This creates a system where the core business logic is isolated from volatile UI and infrastructure details [citation:2].