An adapter for the releasable and relockable coupling of an endoscope with a camera head has an inner wall and an outer wall that are connected with one another via a connecting wall extending between the inner wall and outer wall at or near their first axial ends, and which inner wall and outer wall are arranged with at least a lateral separation from one another, so that an open clearance results between the inner wall and outer wall on a second axial side that is situated opposite the first axial ends. Furthermore, the adapter comprises a coupling wall that seals a clearance enclosed by the inner wall at or near a second axial end of the inner wall, such that the clearance that is enclosed by the inner wall is open at a first axial side that is situated opposite the second axial end of the inner wall.
