Definition of Done

When a Product Backlog item or an Increment is described as “Done”, everyone must understand what “Done” means. Although this varies significantly per Scrum Team, members must have a shared understanding of what it means for work to be complete, to ensure transparency. This is the definition of “Done” for the Scrum Team and is used to assess when work is complete on the product Increment.

Source: http://www.scrumguides.org/scrum-guide.html#artifact-transparency-done