Acceptance criteria
The specific conditions a Product Backlog item must satisfy to be accepted as complete by the Product Owner and stakeholders.
What it means
Acceptance criteria are item-specific, unlike the Definition of Done which applies to every Increment. They describe the functional expectations of a single story: what should happen, in what scenarios, for it to be considered correct.
They are typically written before or during Refinement, giving the Developers a clear target and reducing back-and-forth during the Sprint Review about whether an item truly satisfies the request.
Common mistakes
A common format is Given/When/Then, borrowed from behavior-driven development, which frames criteria as testable scenarios rather than vague statements.
Example
'Given an expired coupon, when a user applies it, then an error message explains it has expired' is one acceptance criterion for a checkout story.