In agile product development a large body of work is often too big to complete in a single iteration. An epic is that large body of work. It is broken down into smaller user stories that can be estimated and delivered incrementally. The epic itself captures a significant feature, customer journey, or business objective that spans multiple sprints.

Epics help teams maintain a high-level view while still working in manageable pieces. They are prioritized in the product backlog and refined as more is learned. Acceptance criteria at the epic level describe the overall outcome; the detailed criteria live in the constituent stories.

Using epics prevents the backlog from becoming an unmanageable list of tiny items while still preserving the discipline of delivering value frequently. When an epic is completed, the team and stakeholders can evaluate whether the intended outcome has been achieved and what should come next.