What describes a window configuration with two sashes that can move past each other?

A window configuration with two sashes that can move past each other is best described as double-hung. This type of window features two operable sashes that slide vertically within the frame. Each sash can be opened independently, allowing for increased ventilation and ease of cleaning, as both the top and bottom sections can be moved up and down. This design is particularly useful in residential settings and can be beneficial in firefighting operations, as firefighters may need to access window openings for ventilation or rescue purposes.

The other types of windows mentioned have different operating mechanisms. For instance, horizontal sliding windows have sashes that slide side to side, pivoting windows rotate around a central point, and casement windows are hinged on one side, swinging outward for operation. These configurations do not allow for the stacking or overlapping movement of sashes, which is a defining feature of double-hung windows.