Scrum is an agile framework used for managing and completing complex projects, primarily in software development. It emphasizes teamwork, accountability, and iterative progress through short cycles called sprints, which typically last two to four weeks. Each sprint begins with a planning meeting and ends with a review and retrospective to assess progress and improve processes. In Scrum, roles are clearly defined, including the Scrum Master, who facilitates the process, and the Product Owner, who represents stakeholders and prioritizes tasks. Teams work collaboratively to deliver small, functional increments of the product, allowing for flexibility and adaptation to changing requirements throughout the project lifecycle.