Waterfall is a sequential approach where each phase (requirements, design, build, test, deploy) must finish before the next begins, which works well when requirements are stable and well understood, such as construction or regulatory compliance projects. Agile, by contrast, delivers work in short iterative cycles called sprints (commonly two to four weeks), allowing teams to adapt based on feedback -- it suits software development and other projects where requirements evolve. Scrum, the most widely used Agile framework, organizes work around a Product Backlog (a prioritized list of features), a Sprint Backlog (work committed for the current sprint), a daily stand-up meeting, and two key roles: the Product Owner (defines priorities) and the Scrum Master (removes obstacles and facilitates the process). Neither approach is universally 'better' -- the right choice depends on how well-defined and stable the project's requirements are.