A phase of a project is a collection of related activities that are part of the larger project lifecycle. Each phase represents a significant portion of the project, characterized by a set of objectives, tasks, and responsibilities that must be completed to move on to the next stage of the project. The PMBOK® Guide outlines that while phases are typically carried out in chronological order, they can be revisited as needed when project changes occur. This approach allows for flexibility and adaptability within the project management process.

References: The information is aligned with the PMBOK® Guide and other PPM reference materials, which describe project phases as major sets of activities within the project lifecycle12.