Definition of ready
Also called: DoR, story readiness, ready for development
The definition of ready is the agreed list of conditions a story must meet before the team starts work on it.
A definition of ready protects a sprint from stories nobody understands yet. Typical conditions are a clear user and outcome, acceptance criteria, known dependencies and a size.
From a testing point of view the condition that matters is testability. A story is ready when someone can say how they will know it works: which data, which environment, which expected result. Estimated is not the same as ready.
I treat the definition as a short checklist used in refinement, not as a gate that blocks every conversation. Its purpose is to move the difficult questions to the day before the sprint instead of the day before the release.