Older sash windows stay up through the use of a rope (called a sash cord) and a counterbalanced lead weight, designed to match the weight of the sash. The sash cord is attached to the side of the sash, runs up the frame and over the top of a small pulley wheel, and then down the other side (hidden behind the frame) to a lead weight. When the sash is raised the weight is lowered, and vice versa.
In modern sash windows and some new timber sash windows, the sash cord and weight system is replaced with spring loaded balances, which are tensioned to make sure that they hold the sash in place rather than pulling it up or letting it drop.
In a sash window, the window panels open by sliding up and down in vertical grooves, possibly aided by a system of cords and balanced weights. The sash is made of window panes and their border.
A sash weight allows one to open a window that slides up and have it stay there, rather than fall back down due to its weight. The weight also offers assistance to the person opening the window, especially if it's heavy. The part of the window that slides up and down is called the sash. The sash weight is a counterbalance connected to the window via a sash cord which goes over a pulley at the top of the window frame. As the window is opened by pulling it up, the sash weight moves down in a space behind the wall and is thus not visible. A more modern way of accomplishing the same task is to use a sash balance, which is a cable or tape wound tightly in a spring-loaded mechanism that offers a certain amount of resistance to the unwinding force of the window opening. A similar use of this pulley system can be found in an elevator with counterweights.
The upright of a sash window is called a stile. There is a diagram showing this and the other names of parts of a sash window at `Windows - Window Sash' http://www.inquirewithin.biz/windows/window_sash.htm.
The bottom wooden part of the window. In this case, the 'sash' is any kind of covering for windows. It could be shutters, a shade, blinds, whatever. Or it could be that the narrator "opened the window".
If it is a sash-window, the ropes which have a weight on one end, and the other end is attached to the window frame (on both sides) has snapped. Once the ropes have snapped, the weight of the window will cause it to fall down. If it is a sash-window, search the internet for repairing a 'sash-window' or contact a local builder/handyman.
Some have counter-weights (sash weights), some have latches that catch the window in certain positions, some have friction strips on the sides that try to hold the window wherever it's set.
From the French word châssis "frame"
pocket windowI belive what you describe is also called a barn sash. That being where they are most often used. One window sash, a sash being one window, most house windows have 2 sash, upper and lower, one sash that either raises, or slides in the wall of a building.
A window sash on hinges
A wooden sash window is subject to harsh conditions and requires a high level of skill to make and to fit to the frame. There are a number of diagrams and a description of window sash and how to fit them in the Audels Builders and Carpenters guide.
A sash window regularly has 2 sashes in which can be slid open. Depending on the retailer and window size, prices for sash windows can differ. One would need to have detailed measurements in order to properly quote prices.
Sash type windows are mainly use for letting in larger amounts of light and airflow compared to other smaller windows. Sash windows have been used in buildings for many years and are a more common sight in older buildings.