A breakdown of project activities into linear sequential phases, where each phase depends on the deliverables of the previous one and corresponds to a specialisation of tasks
The waterfall model is a breakdown of developmental activities into linear sequential phases, meaning that each phase is passed down onto each other, where each phase depends on the deliverables of the previous one and corresponds to a specialization of tasks. This approach is typical for certain areas of engineering design. In software development, it tends to be among the less iterative and flexible approaches, as progress flows in largely one direction (downwards like a waterfall) through the phases of conception, initiation, analysis, design, construction, testing, deployment, and maintenance. The waterfall model is the earliest Systems Development Life Cycle (SDLC) approach used in software development.
The waterfall development model originated in the manufacturing and construction industries, where the highly structured physical environments meant that design changes became prohibitively expensive much sooner in the development process. When it was first adopted for software development, there were no recognized alternatives for knowledge-based creative work.