The word 'importation' commonly refers to the bringing of goods into a customs territory. However this term is not used to describe the customs procedure relating to the clearance of goods brought into the customs territory of the Union.
The procedure allowing non-Union goods to circulate freely throughout the customs territory of the Union in the same way as Union goods is called release for free circulation.
From a customs point of view the release for free circulation changes the status of non-Union goods to Union goods and entails the completion of all formalities laid down for importation.