In Scrum, a method for running software teams, every team keeps a “Definition of Done.” The Scrum Guide by Ken Schwaber and Jeff Sutherland calls it a “formal description of the state of the Increment when it meets the quality measures required for the product.” The rule is strict: “If a Product Backlog item does not meet the Definition of Done, it cannot be released or even presented at the Sprint Review.”
The agile coach Mike Cohn calls the Definition of Done “an agreed-upon set of things that must be true before any product backlog item is considered complete.” One of his examples is that “the code comes with automated tests at all appropriate levels.” Each item also has its own acceptance criteria, and “all of the acceptance criteria (conditions of satisfaction) must be fulfilled.”