A software development lifecycle (SDLC) model is an abstract, high-level representation of the software development process. A SDLC model defines how different development phases and types of activities
performed within this process relate to each other, both logically and chronologically. Examples of SDLC models include: sequential development models (e.g., waterfall model, V-model), iterative development models (e.g., spiral model, prototyping), and incremental development models (e.g., Unified Process).
Some activities within software development processes can also be described by more detailed software development methods and Agile practices. Examples include: acceptance test-driven development
(ATDD), behavior-driven development (BDD), domain-driven design (DDD), extreme programming (XP), feature-driven development (FDD), Kanban, Lean IT, Scrum, and test-driven development (TDD).