Scope definition is the process of clearly outlining the boundaries and deliverables of a project. It involves identifying what is included and excluded from the project, ensuring that all stakeholders have a shared understanding of the project's goals and objectives. This clarity helps prevent scope creep, which can lead to delays and increased costs. A well-defined scope typically includes specific tasks, timelines, and resources needed to achieve the desired outcomes. Tools like scope statements and work breakdown structures are often used to document and communicate the scope effectively, facilitating better planning and execution throughout the project lifecycle.