What term describes a window where both the top and bottom sashes are operable and slide up and down?

The term that describes a window where both the top and bottom sashes are operable and slide up and down is "double hung." This type of window design allows for flexibility in ventilation as either sash can be opened independently. Homeowners often prefer double hung windows because they can be easily cleaned from inside the home, as both sashes tilt inward.

The other terms refer to different window characteristics. For instance, "double" generally suggests two of something but isn't specific to the operation of sashes. "Double hinged" is not a standard term used in window descriptions and may imply a type of door rather than a window. "Double pane" refers specifically to the construction of a window's glass, indicating that it has two layers of glass for better insulation, but does not address the operable sashes.