The Scrum Guide by Ken Schwaber and Jeff Sutherland describes Scrum, a method used by software teams. It defines in writing when a piece of work is finished. “The DoD is 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 DoD, it cannot be released or even presented at the Sprint Review.”