The Waterfall model is a sequential development methodology. In product management, Waterfall is meant to organize the workflow of software development through a series of distinct phases.
It is considered a more linear, “traditional” approach when compared to Agile methodology (which takes a team and sprint-based approach to product development).
When the Waterfall model is used, development is seen as flowing steadily downwards (like a waterfall) through the following phases:
The project is divided into sequential phases, with some overlap and splashback acceptable between phases. However, many Waterfall purists emphasize that each phase is distinct and must be completed in order for the next one to begin. Emphasis is placed on planning, time schedules, target dates, budgets and implementation of an entire system at one time.