This document provides definitions and guidance related to key terms and concepts in the EU Return Directive. It defines terms like third-country national, illegal stay, return, return decision, and removal order. It clarifies what situations constitute illegal stay. It also provides explanations around the definition of return, specifying that returning someone to another EU Member State does not constitute return under the Directive. The document provides important context and interpretations to facilitate a harmonized understanding and application of the Return Directive.