Abstract: In a window comprising a main frame (1), an intermediate frame (3) hinged at the top of the latter and a sash (7) which is journalled as a pivot sash in the intermediate frame, said intermediate frame (3) is provided with an arresting means (5) in the area of the pivoting axis (2), said arresting means normally being engaged with an associate arresting means (6) in the main frame. The arrest can be disengaged by means of a release handle (9) which is placed on the inner side of the main frame (1), and the window can then serve as an emergency exit, as the intermediate frame (3) with the sash (7) is swung clear of the main frame due to a permanent urging of the intermediate frame in its opening direction.