A double hung window has two sashes that can move up and down in the window frame. By being able to open both bottom and top sash of the window promotes airflow and makes them easy to clean.
A slider window has two or more sashes that overlap slightly but slide horizontally within the frame.
A fixed window is a window that cannot be opened, whose function is limited to allowing light to enter.
A bay window is a multi-panel window, with at least three panels set at different angles to create a protrusion from the wall line.
A bow window is a curved bay window. Bow windows are designed to create space by projecting beyond the exterior wall of a building, and to provide a wider view of the outside and typically combine four or more casement windows, which join together to form an arch.