In architectural terms, a fenestration refers to the arrangement, proportion, and design of windows in a building. It includes the size, shape, number, and position of windows on the exterior façade of a building.
On the other hand, a mullion is a vertical or horizontal element that divides a window into smaller sections or panes. It is usually made of wood, metal, or concrete and can be used to support the window structure. Mullions can also be decorative elements that enhance the aesthetic appeal of a building's façade.
In summary, fenestration is the overall design and arrangement of windows, while mullions are the vertical or horizontal elements that divide windows into smaller panes.
Publication date: